In this task, you are given a question and answer for that. The answer will fill in the blank or will complete the unfinished question. Your task is to provide an explanation based on the given question or fill-in-the-blank statement, and answer.

Q: Question: Rick had a rock (Rock A) from 1000 feet beneath the crust's surface. He later dug 3000 feet deeper and got a second rock (Rock B). Which rock is likely older? 
 Answer: Rock B

A: Older rocks are at the bottom and younger rocks are at the top.
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Q: Question: Mary and Clare go to the beach. Mary uses a sunscreen with SPF 45. Clare uses a sunscreen that has an SPF of 20. Who skin will be protected less? 
 Answer: Clare

A: A sunscreen with a higher SPF protects the skin longer.
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Q: Question: Joe noticed that the humidity inside the greenhouse was getting very low, so he turned the sprinklers on to make it more humid. Thus, when the water potential gradient across the inside and outside of the leaf becomes equal, the rate of transpiration will 
 Answer: increase

A:
As humidity increases, the water potential gradient across the inside and outside the leaf become more equal, and so the rate of transpiration decreases.
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