All plants we see today had ancestors that lived in the water. one of the reasons plants began to live on land was decreased exposure to fish that eat plants. decreased competition from other plants. increased exposure to oxygen. decreased exposure to salt in the ocean water.

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.

the correct answer in apex is tissue development, i know because i just had this question