Most of earth’s landmasses are covered by a mixture of bits of rocks and bits of once-living parts of plants and animals. this material is called

Fossil

Fossils are the remains or traces of dead living beings. Fossils are formed when the soft parts of the dead organisms gets decomposed by the action of microbes present in the soil and only hard skeleton is left like stem or bark in plants and bones in animals and humans. These remaining parts are buried under different layers of soil strata. The soil containing dead remains gets compacted in the form of hard rock.

The material formed by bits of rocks and bits of once-living parts of plant is called fossil.

since no one answered yet i will give it a shot, not completely sure tho.

i think it should be y=cos(x+2pi), (third answer, answer c)

good luck.