Final answer:
a. The trematode preferentially infects snails with rare genotypes. The false statement about the studies by Dybdahl and Lively on snails and their parasites is that the trematode preferentially infects snails with rare genotypes.
Step-by-step explanation:
The false statement about the studies by Dybdahl and Lively on snails and their parasites is:
a. The trematode preferentially infects snails with rare genotypes.
The true statements are b. Parasites evolve more quickly in response to snails than snails evolve to parasites, c. The trematode worm castrates males and sterilizes females, and d. The snail genotype that was most abundant at one point often changed from year to year.