Which part of an amino acid is the only one that varies and is what defines its properties?

Ascientist is studying muscle twitches in chicken quadriceps. to activate the muscle, he needs to provide stimulus to the

Prompt compare the three types of volcanic mountains in terms of shape, type of eruption, and the minerals that make up the volcano

What would be the result if crossing over did not happen during meiosis in humans? a. there would be less genetic variation in humans. b. parents would be more likely to look like their children. c. the human population could not reproduce. d. children would have more chromosomes.