Crossing over plays a critical role in increasing the genetic variation among offspring of sexual reproduction. a. True
b. False

Acladogram is a branching diagram that represents suggested evolutionary relationships among organisms based on the presence of unique traits. a scientist discovers a new organism that lacks limbs and does not have a true backbone. the organism lays eggs to produce offspring and has a cartilage-like rod known as a notochord running along its dorsal surface. on the cladogram below, select the species to which the newly discovered organism is most closely related.

All living organisms are composed of a. only one cell. b. at least 100 cells. c. at least three cells. d. one or more cells.

What is the most abundant vertebrate on earth?