Which statement is true about experiments? Experiments can only be carried out by a scientist.
Experiments can only be carried out by a scientist.

Experiments only have dependent variables.
Experiments only have dependent variables.

All experiments have variables.

What is the primary goal of human communities?

How does buring fossil fuels impact does carbon cycle? what large impact does this have on the envirnment?

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