What are the two main categories of ecosystems? a. effective and ineffective b. marine and freshwater c. biotic and abiotic d. aquatic and terrestrial

Which kind of aquatic ecosystem does the photograph most likely show? a. marsh b. swamp c. lake d. river

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

Is there any species that went extinct in recent years due to natural causes (not caused by human interaction). if so, what caused it?