13. pieces of earth's crust move on top of the a. ocean b. mantle c. outer core d. inner core 14. the fact that ice floats on top of water is like the fact that a. the mantle causes earthquakes and volcanoes b. the mantle is colder than the crust c. the less dense crust sits on top of the mantle d. the crust is melting 15. a map of global earthquakes and volcanoes tells you a. where the edges of the continents are b. where the earth is the hottest c. nothing, it looks random d. where the plate boundaries are open

Control of the body is accomplished by which of the following body systems? nervous system and circulatory system endocrine and repertory system circulatory and respiratory systems nervous system and endocrine systems

1. emigration the movement of people from one place to another 2. immigration a situation in which resources are being used up at a faster rate than they can be replenished 3. migration the leaving of one's homeland to settle in a new place 4. overpopulation the movement of people to a new country 5. sustainable development a situation in which the birth rate is not sufficient to replace the existing population 6. underpopulation the ability to meet current needs without reducing the ability to meet future needs 7. unsustainable development the increase in the population of a city 8. urbanization a situation in which the number of people exceeds the available natural resources in an area

Chloroplasts and bacteria are in size. a. similar b. at different ends of the size range c. exactly the same d. none of these