Difference between gametes produced without crossing over and the ones produced with crossing over

Cells destroy body cells infected by a virus or bacteria.

Which of the following was not a major animal on land during the carboniferous period? amphibians insects both a and b none of the above

Which of the following is true of metabolism in its entirety in all organisms? a) metabolism depends on a constant supply of energy from food. b) metabolism uses all of an organism's resources. c) metabolism consists of all the energy transformation reactions in an organism. d) metabolism manages the increase of entropy in an organism.