Identify the main idea of the paragraph down below. How has Earth's population become so farge? What has caused our population to grow so quickly? Many factors cause populations increase One major cause of population growth is a falling death rate. The death rate is the number of deaths compared to the total number of individuals in a population at a given timeOn averageabout 154,080 people die each day worldwide. The death rate has decreased for many reasons. Better health care, more , and cleaner water have helped more peopleyoung and oldlonger, healthier lives.

Study guide for unit 2 ~ lesson 3 ,4, & 5 test, thursday, january 24th lesson 3 vocabulary erosion - deposition - landform- weathering- short answers 1. how do volcanic islands form? 2.why is deposition likely to occur outside a river bend? 3. in what conditions does soil form fastest? 4. which 2 earth’s systems interact to form a coral island? 5. a beach growing in size is most likely the result of 6. which type of islands are formed when a chunk of land breaks off from a larger landmass? long answers explain how plants can grow in small cracks of rock that do not appear to contain soil. lesson 4 vocabulary pollution - toxic - short answers 1. most farmers pollute soil by purposefully adding 2. what is the benefit of contour plowing? . 3. using nuclear power to produce electricity can cause water pollution by 4. why do scientists predict humans will run out of fossil fuels someday? 5.farmer spray crops with fertilizer and weed killer to the crops grow. how might this affect the hydrosphere? list two different ways you use fossil fuels. 1- 2- what are two other energy sources scientists and engineers are researching? 1- 2- lesson 5 vocabulary decompose- recycling - short answers 1. which of earth’s systems do you interact with when you wash your hands? 2. which of earth’s systems is polluted by exhaust gases from buses pollute? 3. why is it important to dispose of electronic devices properly? 4. where do people interact with all four of earth’s systems?