The actual sites of gas exchange within the lungs are the

Alveoli

Explanation:

Gaseous exchange takes place in the alveoli of the lung.

As deoxygenated blood travels through the alveoli, excretory product in the form of carbon dioxide diffuses out through the capillaries and oxygen diffuses in the opposite direction. The now oxygenated blood travels form the lung to the left side of the heart where it is pumped to the rest of the body.

increase soil erosion                                             reduce soil erosion

cattle grazing                                                         hydroseeding

deforestation                                                         contour plowing

                                                                                planting vegetation

plant roots basically hold the top soil

together and stop soil erosion because

in such situation top soil is not removed

during flood but cattle grazing causes

soil erosion because cattle consume the

grasses and herbs and top soil is exposed.

same situation occurs because of

deforestation, the trees and plants are cut

down to expose top soil which causes soil

erosion

your answer should be c) enjoy!