Medical Dictionary. brachial plexus. noun. Medical Definition of brachial plexus. : a complex network of nerves that is formed chiefly by the lower four cervical nerves and the first thoracic nerve, lies partly within the axilla, and supplies nerves to the chest, shoulder, and arm.
Nonrenewable Sources of Energy. Most of the energy we use comes from fossil fuels, such as coal, natural gas and petroleum. Uranium is another nonrenewable source, but it is not a fossil fuel.Uranium is converted to a fuel and used in nuclear power plants.Once these natural resources are used up, they are gone forever.nergy is the power we use for transportation, for heat and light in our homes and for the manufacture of all kinds of products. There are two sources of energy: renewable and nonrenewable energy.
Humans harness energy conversion processes to provide energy services.Energy demand is derived from preferences for energy services and depends on properties ofconversion technologies and costs. Energy commodities are economic substitutes.Energyresources are depletable or renewable and storable or non-storable.ire, providing heat and light, is. a process by which chemical energy stored in the fuel, say, wood, is converted to thermal. energy and radiant energy. Chemical energy stored in wood is the result of photosynthesis, whereby plants convert energy in sunlight to chemical energy, stored in the plant material.