14. Which of the following involves a chemical change? A.mixing
b. melting
grinding
d. decomposing

D. decomposing

General Formulas and Concepts:

Chemistry

Explanation:

A would be incorrect because mixing 2 things together doesn't necessarily create a chemical change. Take oil and water for example. You can mix the 2 and it would not have a chemical change.

B would be incorrect because you are simplify changing the state of matter of the object. Iron in solid form is still iron in liquid form; there is no chemical change.

C would be incorrect for similar reasons as B. You are simply changing the state of matter.

D would be the remaining and correct answer. Decomposing changes one object into a different one by chemically changing.

Multicellular organisms need efficient transportation systems because simple diffusion would be too slow to transport nutrients and remove waste.

Explanation:

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