Which of the following organisms most likely filled the pond first? A flowering plants Blow-growing plants C. tall-growing grasses D. green algae

amber has allowed scientists to study dna that has been preserved over millions of years.

carbon

explanation:

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.