Question: Q: What is the major source of warmth for earth? Read this paragraph and choose the correct option from the provided answers: Earth is warmed by energy that radiates from the sun. Earth radiates some of the energy back into space. Greenhouse gases (GHGs) trap much of the re-radiated energy, causing an increase in the temperature of the atmosphere close to the surface. Choices: - the Moon - seasons - equator - the sun A:
Answer: the sun

Question: Q: What do muscles need to contract? Read this paragraph and choose the correct option from the provided answers: Muscles cannot contract on their own. They need a stimulus from a nerve cell to "tell" them to contract. Let's say you decide to raise your hand in class. Your brain sends electrical messages to nerve cells, called motor neurons, in your arm and shoulder. The motor neurons, in turn, stimulate muscle fibers in your arm and shoulder to contract, causing your arm to rise. Involuntary contractions of cardiac and smooth muscles are also controlled by nerves. Choices: - stress - tendons - pressures - stimulus A:
Answer: stimulus

Question: Q: What are ring-shaped hydrocarbons called? Read this paragraph and choose the correct option from the provided answers: Hydrocarbons may form straight chains, branched chains, or rings. Ring-shaped hydrocarbons are called cyclic hydrocarbons. Choices: - reverse hydrocarbons - curved hydrocarbons - cylindrical hydrocarbons - cyclic hydrocarbons A:
Answer:
cyclic hydrocarbons