Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 34 to 38.

Trees protect the soil beneath them; thus, tree loss can affect soil integrity. ___(1)___, the rainforest floor, home to myriad plant life as well as insects, worms, reptiles and amphibians, and small mammals, relies on a dense canopy of branches and leaves to keep it healthy and intact. Tree roots also stabilize the soil and help prevent erosion. In exchange a healthy soil encourages root development and microbial activity, ___(2)___ contribute to tree growth and well-being. A major factor in logging-related soil damage comes from road building, with trucks and other heavy equipment compressing the spongy soil, creating furrows where water collects, and disrupting the underground water flow. Eventually, the topsoil wears away, leaving behind a ___(3)___ layer of rocks and hard clay.
Logging can also damage aquatic habitats. Vegetation along rivers and stream banks helps ___(4)___ a steady water flow by blocking the entry of soil and other residue, and trees shade inhibits the growth of algae. Removing trees obliterates these benefits. When eroding soil flows into waterways, the organic matter within it consumes more oxygen, which can lead to oxygen depletion in the water, killing fish and ___(5)___ aquatic wildlife.