What are they impacts when people clear all the vegetation from the buffer zone next to a stream in order to build on or farm the land? ?

Vegetation bordering a river bank is termed riparian vegetation. It is thought that the land immediately bordering a river is ecologically sensitive and changes in land use in this zone can have disproportionately large effects on the river. Riparian vegetation may play a role in binding soils of a river bank, and their removal can cause bank erosion, which can change the course of a river or exacerbate the impacts of flooding. Changing land use in the riparian zone, such as farming, can affect the water quality of the river, as return from from irrigated crops of livestock will readily enter the river from this zone,

The answer is a: the eggs have half as many chromosomes as the body cells