Walter and Luis Alvarez hypothesized that an asteroid impact caused the formation of a 66- million-year-old layer of clay containing high levels of iridium. How did geologists test this hypothesis? What evidence did they look for? PLEASE HELP ME FAST!!!

What happens when a magniseum ion ia atracked to a chlrene ion

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

Plsss > .< compare and contrast the characteristics of flatworms rounds worms and earthworms