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Mahaicony Secondary School

Grade 10 Biology
Section A
Handout # 2
Prepared by: Ms. Sabrina Dookie
Syllabus Objectives:
 Discuss the importance of and difficulties encountered in recycling manufactured
 Describe the impact of human activates on the environment;
 Assess the implications of pollution of marine and wetland environments;
 Discuss current and future trends regarding climate change;
 Suggest means by which the environment could be conserved and restored;
 Discuss the factors that affect the growth and survival of populations including human

Population Growth

A population is a group of one species of organism living in the same environment. The
rate at which populations grow depends on the rate of birth, the rate of death, movement into the
population (immigration) and the movement out of the population (emigration).

Factors which affect population growth:

The following factors may affect a population growth:
 Available space
 Food and water supply
 Predator-prey relationships
 Competition among organisms
 Outbreaks of diseases
 Natural disasters

The following graph shows a generalised population growth curve:

Factors which may limit population growth:

The same factors which may encourage populations to grow can limit the size and growth
of the populations. Where there is a shortage of space, food or water successful breeding does
not usually take place, reducing the birth rate and leading to a slower increase. Similarly, where
there are a large number of predators, an outbreak of a disease that spreads through the
population, or natural disaster, the death rate increases. When the death rate exceeds the birth
rate, the population growth declines.

Human Population Growth and its Effects

The humans who live in different areas also form populations. The numbers of people on
Earth have increased steadily over time.
The population of Earth as a whole depends on the relationship between birth and death
rate. Humans can immigrate and emigrate from local populations, but they cannot immigrate or

emigrate from the Earth. As with other species, when the birth rate is higher than the death rate
as it is presently, the population increases.
As mammals, humans have the same needs as other animals. Humans need space, food,
water, they are susceptible to diseases that can kill them and although they have few natural
predators, humans often kill each other in times of war.

Effects of Human Population Growth

The human population on Earth is likely to continue growing quickly in the immediate
future. This has serious implications to Earth and its resources.
As the population increases, people need more food and more space to live on and
to farm to produce more food for the increasing number of people. As a result, more and more
natural areas, including rainforests, are being cleared to make room for farming and housing and
to produce resources for building and other industries. This may lead to increased pollution of
soil and water resources.
Clearing natural areas also puts pressure on other species; it can lead to extinctions and
biodiversity- loss as a result of habitat change and lack of food supplies. The removal or
destruction of abiotic and biotic components of the eco-system can disrupt natural cycles and
threaten our survival as a species.
Natural Resources
Finite Resources:
The following are ways in which we benefit from the natural resources found in our
 Provision of food, fuel and fibre (wood and cloth)
 Provision of shelter and building materials.
 Protection of coastal shores from erosion of waves
 Renewal of soil fertility
 Revenue and employment from tourism
 Provision of medicine
 Natural purification of water and air
 Cycling and movement of nutrients
 Enjoyment and aesthetic benefits.

From an ecological point of view, it makes sense to use these resources carefully and make sure
that they are available for the future. Some persons are highly dependent on natural resources
and the biodiversity of their eco-systems for their survival.

Mineral and Energy Resources

Many of the natural resources we use are renewable. Some resources are not renewable in
our lifetimes. These are called finite resources, because they get used up and cannot be replaced.
The Caribbean is not as rich in mineral resources as some other regions, but we do have minerals
such as bauxite and nickel and energy resources in the form of oil.
Most of our energy needs are supplied by burning fossil fuels like coal, gas, and oil.
Population growth means a greater demand for resources. In addition, modern lifestyles
demand more and more finite resources. This means that if we continue to use them at increasing
rates, they will run out. There is a great need for us to use resources in sustainable ways and to
conserve them for future generations.

Experts agree that humans cannot continue to use the Earth and its resources at current
rates without incurring serious environmental damage, which could in the longer term affect our
ability to produce more food and have access to clean water.

Resources for the Future?

Humans cannot continue to use resources at the present rate without serious economic
and environmental consequences. We need to find ways of protecting the environment and our
economic well-being from the effects of using up scarce resources. In other words, we need to
find means of conserving our resources. There are three main ways of conserving resources:

Reduce, Reuse and Recycle

If there is an increase in population then there will be an increase of

waste. There will be a positive effect if we can reduce what we use.
This is especially the case for surplus packaging used by manufacturers
which is immediately put in the bin. Reusing is using the same materials for
their same intended purposes as before.
Many items can be reused:
 Glass bottles and jars
 Carrier bags
 Paper that has only been used on one side
 Clothes
 Cardboard

Recycling materials means that the waste must first be separated. Householders play a role by
sorting this out by placing the recyclable materials in a separate bin. They can also make use of
bottle banks for glass.
Examples of materials that are recycled are:
 Glass: used in making new bottles, fibre glass and road building materials.
 Paper: used in making newsprint and roofing felt for insulation.
 Metals: used in making cars and tin plating.
 Some plastics: used in making new clothing and insulation.

However, most of the energy used in the recycling process comes from non-renewable resources
which are finite.
However, for recycling to become widespread, it must be economically viable companies will
only recycle if at least one of the following conditions is fulfilled:
 Their products are cheaper than if they did not use recycling.
 They receive subsidies from central or local governments to manufacture products using
recycled materials.
 People are prepared to pay more for recycled products.
 There are many difficulties involved with recycling. The following table shows how
some of these difficulties and how they might be overcome.

Difficulties Encountered Possible solutions

People are apathetic and don’t bother to Incentives, laws which state that certain goods
recycle. have to be recycled, education campaigns,
deposits on containers which are refunded if
they are returned for recycling.
Goods need to be sorted out by type and Councils can issue separate bins.
stored separately.
Items for recycling must be clean and dry. Education campaigns, volunteers can help with
cleaning goods for recycling.

Plastics are bulky and heavy when they are Reduce plastic use; develop new methods of
compacted, so it is expensive to transport. recycling that is low cost and effective.
It takes time and money to sort items at Add special subsidies and tax breaks for
depot. companies to encourage them to employ
people to do this.
Not all paper and glass can be recycled. Separate containers for office and clean paper,
bins for different coloured glass.
Recycling outlets may not be accessible to Consult with the community to find the best
everyone. location, use local shopping centres and other
community centres.
Recycling companies will not pick up small Organise local collection and dumping depots
individual loads. so that loads can be picked up.
Large companies may not recycle unless Laws and regulations to force companies to
they see some economic benefit. recycle, fines and penalties, educating
companies about the importance and benefits
of recycling.

If we practice the three R’s then we can:

 Reduce pollution
 Reduce costs
 Save the environment
 Reduce energy use
 Create jobs and income
 Save natural resources
 Save valuable products

Environments under Threat

Human activities are all the things that we do as we go about our daily lives. This
includes work activities such as farming, mining, manufacturing and waste disposal.

Habitat loss

Loss of habitats and eco-systems is one of the negative effects of human activity. When
people cut down forests, plough up natural vegetation, trawl or mine seabed and fill in the
wetlands, they change the natural habitat of the species that live there. This change forces species
to migrate or die out. They also disrupt important reactions between organisms in an eco-system.

Invasive and Indigenous Species

Alien species are those that do not occur naturally in an environment. When alien species
are inducted in an environment on purpose or accidentally, they can become invasive. An
invasive species is one that takes over the niche of the indigenous species and threatens eco-
systems. Alien species become invasive when they are introduced in areas that do not have
natural predators that keep their populations in check.

Population Pressure and Overconsumption

Since the human population is increasing, there will be a need for more food, shelter, and
space for roads and buildings, and other resources to supply our needs.
Modern technology and developments and farming and other industries have led to more
intensive use of land and other resources. This can lead to destruction of the environment in
areas like forests, coral reefs etc.

What is Pollution?
Pollution is the alteration of the Earth’s environment by the actions of humans. It is the
result of the release by humans of the damaging materials or energy into the environment.
The material or energy released is called a pollutant.
A useful distinction can be made between pollutants in nature. They can be:
 Biodegradable: these are pollutants that can be broken down in nature. They are capable
of decomposing.
Examples are: paper, cardboard, food, cloth etc.
 Non-biodegradable: these do not break down, but accumulate.
Examples are: metals, glass, plastics etc.


Pollution may cause muddy landscapes, poison soils and waterways, or kill plants and
risk of contracting deadly diseases.

Pollutants may be:

 Domestic waste: household garbage such as plastics, tins, paper, waste food etc.
 Industrial waste: waste oil, toxic chemicals, carbon-dioxide, sulphur dioxide, smoke,
soot etc.
 Agricultural waste: fertilisers, sewage

Pollution may be of air, water or land.

Air Pollution:
There are three main problems with the Earth’s atmosphere:
 The Greenhouse Effect
 Changes to the ozone layer
 Production of acid rain

The ‘Greenhouse Effect’

Greenhouse gases trap infrared radiation (‘heat’) close to the Earth’s surface. Solar
radiation is allowed to enter the lower atmosphere but is not allowed to escape. The greenhouse
effect is increasing because of the raised level of greenhouse gases:
 Carbon-dioxide: released by the combustion of fossil fuels in power plants and
internal combustion engines of vehicles.

 Methane: produced in the guts of ruminants such as cows, and in the waterlogged
conditions of swamps and rice fields.
 CFC’s (chlorofluorocarbons) from aerosol propellants and refrigerator coolants.

Global warming (raised temperature of the Earth’s surface) causes:
 Greater climatic extremes: stronger winds, heavier rainfall and unseasonal weather.
 Melting of polar ice caps and changes to the density of sea water: rising sea levels and
 Evaporation of water from fertile areas: deserts may form.
 Pests may spread to new areas.
To limit the effects of greenhouse gases, humans should:

 Reduce burning fossil fuels: explore alternative sources of energy.
 Reduce cutting of forests for cattle ranching or rice growing.
 Replant forests.


Examining Global Greenhouse Gas Emissions
(Taken from the United States Environmental Protection Agency)


 Carbon dioxide (CO2) - Fossil fuel use is the primary source of CO2. The way in
deforestation. CO2 can also be emitted from direct human-induced impacts on forestry
reforestation, improvement of soils, and other activities.

 Methane (CH4) - Agricultural activities, waste management, energy use, and biomass
burning all contribute to CH4 emissions.

 Nitrous oxide (N2O) - Agricultural activities, such as fertilizer use, are the primary
source of N2O emissions. Biomass burning also generates N2O.
 Fluorinated gases (F-gases) - Industrial processes, refrigeration, and the use of a
Black carbon is a solid particle or aerosol, not a gas, but it also contributes to warming of the

Global Greenhouse Gas Emissions by Economic Sector

their production:

 Electricity and Heat Production (25% of 2010 global greenhouse gas emissions) -
source of global greenhouse gas emissions.

 Industry (21% of 2010 global greenhouse gas emissions) - Greenhouse gas emissions
from industry primarily involve fossil fuels burned on-site at facilities for energy. This
sector also includes emissions from chemical, metallurgical, and mineral
transformation processes not associated with energy consumption and emissions from
waste management activities. (Note: Emissions from industrial electricity use are
excluded and are instead covered in the Electricity and Heat Production sector.)
 Agriculture, Forestry, and Other Land Use (24% of 2010 global greenhouse gas
emissions) - Greenhouse gas emissions from this sector come mostly from agriculture
(cultivation of crops and livestock) and deforestation. This estimate does not include
the CO2 that ecosystems remove from the atmosphere by sequestering carbon in
biomass, dead organic matter and soils, which offset approximately 20% of emissions
from this sector.

 Transportation (14% of 2010 global greenhouse gas emissions) - Greenhouse gas
emissions from this sector primarily involve fossil fuels burned for road, rail, air, and

marine transportation. Almost all (95%) of the world's transportation energy comes
from petroleum-based fuels, largely gasoline and diesel.
 Buildings (6% of 2010 global greenhouse gas emissions) - Greenhouse gas emissions
from this sector arise from on-site energy generation and burning fuels for heat in
buildings or cooking in homes. (Note: Emissions from electricity use in buildings are

 Other Energy (10% of 2010 global greenhouse gas emissions) - This source of
greenhouse gas emissions refers to all emissions from the energy sector which are not
directly associated with electricity or heat production, such as fuel extraction, refining,
processing, and transportation.

Trends in Global Emissions

Global Carbon Emissions from Fossil-fuels 1900-2011

Global carbon emissions from fossil fuels have significantly increased since 1900. Since 1970,
largest contributors. Emissions of non-CO2 greenhouse gases have also increased significantly
since 1900.

2011 Global CO2 Emissions from Fossil Fuel Combustion and Some Industrial Processes by

Union, India, the Russian Federation, Japan, and Canada. These data include CO2emissions from
represent a large proportion of total global CO2 emissions.

Emissions and sinks related to changes in land use are not included in these estimates.
However, changes in land use can be important: estimates indicate that net global greenhouse gas
emissions from agriculture, forestry, and other land use were over 8 billion metric tons of
CO2 equivalent, or about 24% of total global greenhouse gas emissions. In areas such as
the United States and Europe, changes in land use associated with human activities have the net
effect of absorbing CO2, partially offsetting the emissions from deforestation in other regions.

The Ozone Layer

Low Level Ozone
 Combustion of fossil fuels. Nitrogen oxides
increase low level ozone.

Low level ozone is dangerous because it:
 Acts as a greenhouse gas
 Traps dust, smoke, causing smogs.
 Causes irritation of the eyes, nose, throat and lungs.
 Damages mesophyll layer in leaves, reducing yield of crops.

To reduce the level of low-level ozone humans should reduce the burning of fossil fuels and
explore alternative sources of energy.

High Level Ozone
Chlorofluorocarbons (CFC’s) used in aerosols, refrigerator coolants and expanded plastics
release chlorine.
This decreases high-level ozone.

High level ozone absorbs solar ultraviolet radiation,
so decreased ozone mans increased risk of:
 Skin cancer
 Cataracts
 Mutations
 Sunburn

To limit the damage to the ozone layer, humans should use less CFC’s.
CFC’s are very long lived, and those already in the atmosphere will
take 100 years to degrade. This may cause holes to form in the ozone layer.

Acid Rain

Human activities release acidic gases:
 Sulphur and nitrogen in fossil fuels are converted into oxides during combustion.
 More oxidation occurs in the clouds. Oxidation is catalysed by ozone and by unburnt
hydrocarbon fuels.
 These oxides dissolve in water and fall as acid rain.


Acid rain can cause problems:

 Soils will become more acidic. This will cause leaching of
minerals and inhibition of decomposition.
 Water in lakes and rivers collects excess minerals.

This causes death of fish and invertebrates and food chains
are disrupted.
 Forest trees suffer starvation because of leaching of ions
and destruction of photosynthetic tissue.

Acid rain can be reduced:
 Clean up emissions from power stations with scrubbers.
 Clean up exhaust emissions with catalytic converters.


This occurs when visibility is reduced by water vapour and trapped chemicals in still air.
There are two types of smogs:
 Smoke together with a high concentration of sulphur dioxide makes ‘reducing smog’.
These cause an increase in deaths and diseases.
 Photo-chemical smogs: this type of smog is made from sunlight. It irritates the eyes and
damages young plants. It is very unpleasant because it does not allow sunlight to pass
through and makes it difficult to see.
Carbon –monoxide

This is an invisible gas with no smell. It is poisonous if inhaled in large amounts. This is
because carbon monoxide binds with haemoglobin, reducing the oxygen carrying capacity of
blood. Carbon monoxide is found in the fumes of:
 Car exhausts
 Badly fitted gas appliances
 Burning cigarettes
Carbon-monoxide is known to cause some serious health risks.

Lead compounds are added to petrol to prevent ‘knocking’ (insufficient burning of the
petrol-air mixture). They are released into the atmosphere as exhaust gases.

Lead compounds are absorbed into the body from the air and may:
 Slow down mental development
 Damage the liver

Reduce the use of ‘leaded’ petrol and use unleaded petrol.



 Inefficient and incomplete combustion of fossil fuels.
 Less light can penetrate the atmosphere.
 Smoke deposit cover leaves.
 Particles in smoke can also irritate the eyes, noses and lungs.
Some can be very poisonous.

Smoke emissions are reduced by:
 More efficient burning, in well designed furnaces.
 Burn ‘smokeless’ fuels.
 Don’t burn toxic materials such as plastic in the open.

Water Pollution
The causes of oxygen depletion:
All living organisms depend on a supply of water. Some organisms live inside water. Any
changes to the oxygen concentration of water can seriously affect the suitability of water as a
The two pollutants that most often reduce oxygen in water are:
 Fertilisers: nitrates and phosphates are added to soil by farmers. Some of the fertiliser
is washed away from soil by rain into the nearest waterway. This is called ‘leaching.’
 Sewage: this contains an excellent source of organic food for bacteria, and also
contains phosphates from detergents.

How Fertilisers and Sewage affect the Oxygen Concentration

“The term 'eutrophic' means well-nourished; thus, 'eutrophication' refers to natural or
artificial addition of nutrients to bodies of water and to the effects of the added nutrients….When
the effects are undesirable, eutrophication may be considered a form of pollution.” - National
Academy of Sciences, 1969

Water that contains a few nutrients is rich is oxygen and supports a wide variety of living
organisms. The oxygen enters the water from the atmosphere by diffusion and from
photosynthesising aquatic plants.
Simpler forms of life, such as algae and bacteria, are controlled because of the low
concentration of nutrients such as nitrate is a limiting factor for their growth. If more nutrients
are available, from fertilisers or sewage, then:
 Algae and other surface plants grow quickly, and block out light to plants rooted at the
bottom of the river or pond.
 The rooted plants die, and their bodies provide more nutrients.
 The population of bacteria increases rapidly. As they multiply, the bacteria consume
more nutrients for aerobic respiration.
 Other living organisms cannot obtain enough oxygen. They must leave the area, if they
can, or they will die. Their bodies provide even more food bacteria, and the situation
becomes even worse.
 The pond or river may eventually become depleted of living organisms.

Effects: (Before and After)

 Treat sewage before it enters rivers.
 Prevent farmyard drainage entering ponds and rivers.
 Control use of fertilisers:
- Apply only when crops are growing
- Never apply to bare fields
- Do not apply when there is a forecast
- Do not dispose of waste fertilisers into rivers and ponds
 Bubble a stream of air through badly polluted ponds.

Oil Pollution


Oil tankers spill their contents, by accident or deliberately, into the sea. Occasionally
damage to pipelines at oil terminals causes enormous discharge of oil into the environment.


Most of the oil floats on the surface of the water, causing:

 Death of sea birds since feathers loses their ability to insulate when they are coated
with oil.
 Fish are directly poisoned.
 Marine animals are killed by eating poisoned fish or loss of fur’s insulating capacity.
Oil is washed unto beaches causing:
 Death of organisms-both plants and animals.
 Loss of tourism.

 Strict control of oil handling.
 Severe fines for breaking the rules concerning oil handling.
 Bioremediation: using living organisms to clear up
pollution. For example, some bacteria can consume oil if fed with a source of sugar.
 Volunteers may wash sea birds and mammals with detergents to remove oil.
Thermal Pollution

Water is used as a coolant:
 In power stations
 In industries, especially metal working and chemical
The water cools the process but is itself warmed up. This hot water is then discharged into the
river or sea.

Temperature of the river is raised, which:
 Lowers the oxygen concentration of the water because the solubility of the water falls as
the temperature rises.
 Causes aquatic organisms to become more active so they consume more oxygen.
 Allows colonisation of foreign species, which may affect food chains.

 Control output of hot water so that it is rapidly cooled by the river or sea.
 Do not allow discharge of hot water into still or slow-moving rivers or canals.


Over use of pesticides on agricultural land or directly on water can raise pesticide levels in water.
The pesticide levels are then amplified as they pass through food chains.

High concentrations of pesticides may accumulate in the tissues of top carnivores. The pesticide
may be toxic or may affect their metabolism.

 Use degradable pesticides
 Explore alternative methods, such as biological pest control.
 Crops that are genetically modified to resist attack by insects may reduce the need to use

There is no way radioactivity can be ‘treated’. The only way that radioactive waste can be
dealt with is to store it. Some radioactive elements have a short half-life, of only days or weeks.
However, some elements have a half-life of thousands of years. This means that the waste must
be kept secure for a very long time, where it cannot leak into the environment. Various ways of
dealing with radioactive waste have been tried:
- Sealing it above ground in containers of lead, concrete or glass.
- Depositing it in sealed containers in deep, underground stores.
- Dumping it in sealed containers in the sea.

Coral Reefs in the Caribbean
(Taken from: ‘Rainforests of the Sea Ravaged’: Overfishing and Pollution Kill 80% of Coral on
Caribbean Reefs. Michael McCarthy. The Independent UK 18 July, 2003)

Coral reefs are thought of as ‘the rainforests of the sea’ because of the richness of their wildlife.
About 80% of coral reefs in the Caribbean have been degraded by human activities.
Pollution from the land is the main cause of coral reef degradation throughout the world.
In the Caribbean, approximately 80% of ocean pollution originates from activities on land. As
human populations expand in coastal areas, development alters the landscape, increasing runoff
of water from the land. Run-offs carry large quantities of:
- Sediment from land clearance and storm drains.
- High levels of nutrients from agricultural areas
- Sewage outflows
- Pollutants, such as petroleum products and pesticides.
These sources of pollution destroy coral reefs and interfere with their ability to feed and
reproduce increased nutrients, such as phosphate ions and nitrate ions from fertilisers, lead to
increased algal growth on reefs, crowding out corals and significantly degrading the eco-system.
Sewage discharge and run off may also introduce pathogens into coral reefs eco-systems.
Pesticides interfere with coral production and growth.

Hard corals are made by tiny animals which slowly build coral reefs from the calcium
carbonate that they excrete. A study found that in 1977 a typical Caribbean reef was 50%
covered in live corals, which is regarded as healthy. By 2002, a typical reef was only 10%
covered, which is regarded as potentially fatal.
Debris also affects reefs in many areas. Marine debris is any human-made object which is
discarded, disposed of, or abandoned and enters coastal and ocean waters. Debris (such as
plastics, metals, bags, hard hats, fishing lines, rubber tyres, glass, and old boats and ships) may
enter directly from a ship or indirectly when washed out into sea via rivers, streams and storm
Plastic debris kills several reef species. Derelict a d abandoned fishing nets and other gear
entangle and kill reef organisms and break or damage reefs. Even remote reef systems suffer the
effects of marine debris. Overfishing removes species that keep other species in control. When a
whole trophic level or algae-eating fish is removed, algae grow and make it difficult for coral to
survive. Some of the decline in the coral community occurred in the early 1980s when there was
a mass die-off of a sea urchin species that grazed on algae on coral reefs
Caribbean reefs host extraordinary biodiversity, provide a livelihood to millions of people
and provide essential physical protection from tropical storms. There is a renewed urgency for
conservation action to restore this unique and important eco-system.
Land Pollution
Many of the pollutants described already have an effect on land also, for example:
 Lead and mercury compounds may poison areas of land.
 Pesticides may enter land based food chains.

 Acid rain may affect the availability of minerals in the soil.
Pollution also includes loss of wildlife habitat and results from human competition for land.

This is the rapid destruction of woodland. The removal of woodland provides firewood,
building materials, cleared land for crops or for grazing cattle. Today, the ‘slash- and-burn’
method is used for clearing land. Humans using the land gain a short-term benefit, but the
damage to the wildlife habitats is immediate and humans also suffer in the long term.
There are many causes of deforestation. The WWF reports that half of the trees illegally removed
from forests are used as fuel.
Some other common reasons are:
- To make more land available for housing and urbanization
- To harvest timber to create commercial items such as paper, furniture and homes
- To create ingredients that are highly prized consumer items, such as the oil from palm
- To create room for cattle ranching
The concentration of humans and their machines into small areas create disturbances so
that animals may stop breeding. In addition roads separate one area from another and the wildlife
areas become fragmented into pieces that are too small to support stable populations of animals
and plants. This is quite devastating to wildlife.

Effects of Deforestation:

Reduction in soil fertility:
 Deciduous trees may contain 90% of the nutrients in a forest eco-system. These nutrients
are removed if these trees are cut down and taken away.
 Soil erosion may be rapid in the absence of trees because of the wind and direct rain may
remove the soil, and the soils structure is no longer stabilised.
Flooding and Landslips:
 After deforestation, water may accumulate rapidly in river valleys (since there are no
trees to absorb the water) often causing landslips in steep hillsides.
Changing in the recycling of materials:
 Atmospheric CO2 concentration may rise since there is less CO2 being absorbed by
plants for photosynthesis.
 Atmospheric O2 is diminished as less is produced by photosynthesis.
 The atmosphere may become drier and the soil wetter as evaporation from the soil is
slower than transpiration.
Climate changes:
 Reduced transpiration rates and drier atmosphere affect the water cycle and reduce
 Rapid heat absorption by bare soil raises the temperature of the lower atmosphere in
some areas, causing thermal gradients which result in more frequent and intense winds.
Species extinction.


is tempting enough for deforestation to continue.

cover. It is a practical solution and is very feasible.
