Explain the idea that life relies on death

The idea that life relies on death is true because living things can be formed from the things which remains after the death of organisms by dead body. By dead bodies remaining material, we make many items for our survival. The other point is that the death is necessary because if the death rate will become less and birth rate will be increased then there will be shortage of needs which are essential for our survival.

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.

not only is it colder, it also becomes darker, less salty, and more dense.