Problem: David was interested in climate change issues. He realized that to understand climate change issues he first needed to distinguish between the terms weather and climate. To that end, he labeled weather as term A. Then he labeled climate as term B. He found it easier to understand their differences in that way. Which changes less frequently, term A or term B?

A: term B

Problem: Mark works as a scientist for a molecular research institute. Today, he has three samples of molecule in front of him, sample A, sample B, and sample C. Sample A is a straight-chain molecule; sample B is a branched-chain molecule; and sample C is a cyclic molecule. Mark's job is to determine the characteristics of each sample. Which sample would have lower boiling point, sample A or sample C?

A: sample A

Problem: David got five exercise tips from his personal trainer, tip A, tip B, tip C, tip D, and tip E. Tip A involves weight lifting, but tip B does not involve weight lifting. Tip C involves running, but tip D does not involve running. Finally, tip E does not involve any exercise at all. David has to find out which tips are most useful for him. Would tip C make the cardiac muscle more efficient or not more efficient than tip D?

A: more efficient

Problem: To reenact James Watt's experiment, John sealed some water in a container. He called this stage of his experiment as stage A. Then he started heating the water in the sealed container. He labeled this stage as stage B. Once the temperature reached hundred degree centigrade, he added more heat to it. He called this stage as stage C. Once all the water has turned into steam, he kept adding heat to it. He called this last stage of is experiment as stage D. At which stage the water would not bigin to vaporize, stage B or stage C?

A:
stage B