Main function – upwards water transport. The xylem, vessels and tracheids of the roots, stems and leaves are interconnected to form a continuous system of water-conducting channels reaching all parts of the plants. The system transports water and soluble mineral nutrients from the roots throughout the plant.
The most likely answer is B, increased significantly. This is so, because of the vast amount of cars, and factories, still in use.So, based upon the statistics and the levels of pollution all over the world, I would have to answer B.
They're considered to be human like hands. They have a thumb like humans which allows them to grip onto trees and maneuver better. It also helps them with their grip onto branches and trees because they rarely come down from up there, so they need to be able to grip tightly even a sleep. I would say it's natural selection due to evolution.
