Which of the following allows animals to sense and respond rapidly to stimuli?

What is called the "building block" of life?

Ecologist have observed a sharp increase of sulfur dioxide in the air . what might be a possible consequence of excessive sulfur dioxide in the air ? a. acid rain b. ozone layer depletion c. ozone layer hole d. increase in sea levels

Long-period comets come from the oort cloud particles in earth’s atmosphere material from the asteroid belt the kuiper belt