Answer D is correct, because an individual can't change his/her own genes in a certain way through certain activities. Mutations certainly occur during an organism's lifetime, but they are completely unpredictable, and very unlikely to take place in reproductive cells like eggs and sperm. Answers A, B, and C are all related to the Lamarckian idea that traits acquired during the lifetime can be passed to offspring. This is important to bring up with students several times because it is such an ingrained idea.
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