Shells are considered biotic because they come from living things. Biotic describes something living or use to be living such as plants and animals. So shells are considered biotic because they come from a living organism.
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The anser is D) Plastids in roots cells are large and designed to store water for later use.
Enzymes lower the activation for chemical reactions so they get a faster *Jump Start.* Once this happens these reactions can happen a lot faster than similar reactions or the same reaction