Describe how a change in the environment could lead to increased immigration or emigration.

A change in environment could either make people leave that place or go to that place. An example of each:

Immigration: Weather is nice and sunny most of the time. People like good weather so they move there

Emigration: Snow storm happens at a place. People can't do anything and they will leave that place since it's an unfavorable place to live in.

A change in environment could either increase immigration or emigration.  

Explanation:

Immigration: If there is a drought, herbivores like rabbits and deers would leave the drought area due to lack of food.

Emigration: if there’s a lot of rain, herbivores like rabbits and deers would move to the rany area due to increase of food.

youre right there are

d. planting trees

the trees take in carbon to make oxygen.