2020年新高考Ⅱ卷（海南） Passage D

Rainforestsare home to a rich variety of medicinal plants, food, birds and animals. Canyou believe that a single bush(灌木丛)in the Amazon may have more species of ants thanthe whole of Britain! About 480 varieties of trees may be found in just onehectare of rainforest.

Rainforestsare the lungs of the planet-storing vast quantities of carbon dioxide andproducing a significant amount of the world’s oxygen. Rainforests have their ownperfect system for ensuring their own survival; the tall trees make a canopy(树冠层)of branches and leaves which protect themselves, smaller plants, and the forest animals from heavy rain, intense dry heat from the sun andstrong winds.

Amazingly, the trees grow in such a way that their leaves and branches, although closetogether, never actually touch those of another tree. Scientists think this isthe plants’ way to prevent the spread of any tree diseases and make life moredifficult for leaf-eating insects like caterpillars. To survive in the forest, animals must climb, jump or fly across the gaps. The ground floor of the forestis not all tangled leaves and bushes, like in films, but is actually fairlyclear. It is where dead leaves turn into food for the trees and other forestlife.

Theyare not called rainforests for nothing! Rainforests can generate 75% of theirown rain. At least 80 inches of rain a year is normal-and in some areas theremay be as much as 430 inches of rain annually. This is real rain-your umbrellamay protect you in a shower, but it won’t keep you dry if there is a fullrainstorm. In just two hours, streams can rise ten to twenty feet. The humidity(湿气)of large rainforests contributes to the formation of raincloudsthat may travel to other countries in need of rain.