They construct dams and create an ecosystem for other species . Because of their dam building nests become available for birds, fish population increases and waterfowl population goes up
Answer: you arre to write a hypothises which is your perspective basically
Explanation:
I think the correct answer from the choices listed above is the last option. It is the need for oxygen that affects the heart rate in mammals. Depending on the needs of these organism, the oxygen needed for the processes inside the body varies which then affect the heart rate.
