6. In the environment, materials causing biomagnification
A) get recycled quickly
B) decompose only in soil
C) remain as permanent residues
D) are stored in less amount in trophic levels

The correct answer is Option C) remain as permanent residues.

Explanation:

Biomagnification is a process in which harmful or toxic substances collected in the body of living organisms as a permanent part of the organism. The toxic substances are not decomposed by microorganisms such as bacteria. The concentration of toxic materials is increased with the increased in trophic levels.

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.