Answer:
I believe the options are:
a. How many other mammals eat trees or other plants to survive?
b. How many other mammals live in an environment that includes water?
c. Do most other mammals have body structures adapted to the places where they live?
d. Do most other mammals change the environment to meet their survival needs?
Explanation:
Beavers, the largest rodents in North America, are classed as a keystone species i.e their presence affects other organisms as well as the abiotic factors in an ecosystem. Beavers enhance the habitat quality of a particular region and make it habitable for other organisms.
- Beavers build dams that form wetlands that are home to majority of species in North America.
- They filter water from silt and increase the quality of water.
- They are "ecological indicators" i.e. they can help establish the health status of an ecosystem.
