Why is still water an ideal environment for the formation of mold and cast fossils? Sediment builds up over organisms. Sediment turns organisms into rock. Hard tissue decays under sediment. Soft tissue is preserved under sediment.

Option A, Sediment builds up over organisms.

The correct answer is A. Sediment builds up over organisms

Explanation:

Mold and cast fossils are formed as one organism (for example, an animal or plant) leaves an impression on a surface. This occurs when organisms decompose and sediment such as minerals builds up, which leads to the impression of organisms to harden and remain over time. This means the organism's impression remains to create a three-dimensional mold or cast.

The formation of these fossils is more common in environments such as still water because in this, due to the lack of flow or changes sediments easily build up over organisms, and therefore a cast or mold forms. According to this, the reason still water is an ideal environment for the formation of mold and cast fossils is that sediment builds up over organisms.