When two experiments are identical except variable, the experiment is called an

Which element is used in photosynthesis found in atmosphere and fixed by bacteria?

Which of the following was not a major animal on land during the carboniferous period? amphibians insects both a and b none of the above

Aragonite shells of clams, snails, or scleractinian corals may be preserved unaltered in cenozoic deposits, but they are generally dissolved or recrystallized in older deposits. true or false