X-rays are electromagnetic waves that can penetrate skin, but not bone. In hospitals, X-rays are used to produce images of bones. How do X-rays compare to visible light?
A.
Visible light has a higher frequency and carries more energy than X-rays.
B.
Visible light has a higher frequency and carries less energy than X-rays.
C.
X-rays have a higher frequency and carry more energy than visible light.
D.
X-rays have a higher frequency and carry less energy than visible light.
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I’m doing some practice exam questions for biology, and i’m not sure how to do these 3 parts to the question.

Juan and carol were studying invertebrates in biology. they knew that segmented or earth worms preferred a dark, moist habitat. during this lab, they would be investigating the responses of organisms called planaria or dugesia tigrina. these were simple flatworms that still had a one-way digestive system and a very simple nervous system. juan and carol placed the planaria in a petri dish containing cool, distilled water that was partially covered with black paper. they shined a light on the dish. next, they removed the paper and placed a small amount of chicken liver at one end of the dish. they added a few large salt crystals to the water. finally, they added drops of hot water to the cool water in the petri dish. their results can be seen in the data table. according to their experiment, all but one conclusion is valid.

Crossing over is a method of (blank)?