Ques:Q: Chemical reactions always involve what? Choices: - fuel - heating - physical change - energy A:

Ans:energy
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Ques:Q: Which types of waves are used for cell phones and radar? Choices: - light waves - thermal waves - sound waves - microwaves A:

Ans:microwaves
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Ques:Q: An enzyme is an organic catalyst produced by what? Choices: - DNA - the liver - amino acid - living cell A:

Ans:living cell
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Ques:Q: Vectors along the same line can be what to one another like ordinary numbers? Choices: - noted - taken - lost - added A:

Ans:
added
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