10 points
independent variables:
a. can't be manipulated
b. can be manipulated
c. none of these answers

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

Which of the following best describes the relationship between glucose and complex molecules such as hormones?

Several billion years ago which gas was the least prevailant in the atmosphere