Astructure that an animal possesses that serves no function, has a reduced function, or serves a different function than it did in its ancestors is called a(n)

The question is incomplete as it does not have the options-

a. superfluous organ

b. extra appendage

c. vestigial structure

d. living fossil

e. chromosomal aberration.

The correct answer will be option-vestigial structure

Explanation:

Vestigial structure  are the structures which do not play any role in the organisms but still are inherited from the ancestors to maintain the fitness of the organisms.

Vestigial organs are found in many organisms including humans in which the presence of vermiform appendix do not play any role but it used to play roles in the ancestors of humans as they carried the cellulose-degrading bacteria.

Thus, a vestigial structure is the correct answer.

answer: tributaries flow into rivers.

wetland is a biome that develops when the water gets accumulated in a land exhibiting a huge depression. these form either seasonally or permanently. the water in the wetland comes from rivers, lakes, ocean, flood, rain or other sources. the wetlands includes mangroves, marshes and peatland.

tributaries flow into the rivers develops a wetland because such water will get deposited in the depression and will restrict the original flow of tributary water. hence, water with low drainage current combines with the river water.