Plant perception (physiology) auxin redistribution occurs in a way to produce differential growth away from gravity. For perception to happen, the plant must sense, perceive and translate the direction of gravity. Without gravity, proper orientation will not occur and the plant will not effectively grow. The root will not be able to uptake nutrients or water, and the shoot will not grow towards the sky to maximize photosynthesis. Plants do not have a brain or neuronal network, but reactions within signalling pathways may provide a biochemical basis for learning and memory in addition to computation and problem solving. Controversially, the brain is used
Natural population growth Natural population growth Natural population increase (in contrast to total population increase) happens as people are born (in contrast to immigration) into a country, and decrease as people die (in contrast to emigrate). Rates of population growth, usually expressed as a percentage, vary greatly. The immigrating population has increased by a huge margin in the past few years. Due to this rising trend of migration it is important that we look into how migration has affected the population, and the trends that follow with it. The countries that are to be looked into are Denmark, Finland, Iceland, Norway and Sweden.