A chemical change occurs when a piece of wood . a. is split
b. is painted
c. decays
d. is cut

Chemical change leads to the formation of new substances. A chemical change is said to have occurred when the piece of wood decays.

A chemical change is said to have occurred when new substances are formed. Hence, in a chemical change, one substance is converted into another.

When a piece of wood decays, a cascade of chemical transformations occur leading to a change in the composition of the wood and carbon dioxide is produced.

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the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.