Which describes primary succession, but not secondary succession? a. Small trees and shrubs replace grasses and other small plants.
b. Large trees replace small trees and shrubs.
c. The process often begins on lifeless, barren rocks that form from a
volcanic eruption
d. The process often begins after a human disturbance, such as clear-cutting a
forest

The embryos of a bird, a reptile, and a mammal are similar in appearance. how does comparing the physical appearance of embryos of different species support the theory of evolution? a. it shows that these organisms share a common ancestor. b. it provides evidence that these organisms eat the same foods. c. it shows that these organisms share the same habitat. d. it provides evidence that these organisms suffered a genetic mutation.