Which of the following statements is true about niches? I. New species can outcompete native species to fill a niche.
II. Extinction or emigration of a species can leave a niche vacant.
III. Some species occupy niches that no other species can fill.

Which of the following best describes homeostasis? a. keeping the internal environment in a stable state b. keeping the external environment in a stable state c. beneficial characteristics resulting from mutation d. reproduction that results in offspring identical to the parent.

An easy way to calculate the amount of energy available at each level is to what?

What is the name of the two satelites on mars