If there are 72 donors in all, how many of them are at the silver level?

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

Which locations on the map are low-pressure areas? a b c d e

Cells must be in osmotic equilibrium with their surroundings environments because if they swell or shrink thier membranes will rupture