Question: Q: What is the major source of warmth for earth? Choices: - the Moon - seasons - equator - the sun A:
Answer: the sun

Question: Q: What do muscles need to contract? Choices: - stress - tendons - pressures - stimulus A:
Answer: stimulus

Question: Q: What are ring-shaped hydrocarbons called? Choices: - reverse hydrocarbons - curved hydrocarbons - cylindrical hydrocarbons - cyclic hydrocarbons A:
Answer:
cyclic hydrocarbons