Unlike secondary succession, primary succession
a. occurs in an area where existing communities still exist.
b. proceeds at a much faster rate.
c. has the challenge of occurring in areas where no community exists at all.
d. leads to an increased number of different species over time.

Red–green color blindness is an x-linked recessive trait in humans. polydactyly (extra fingers and toes) is an autosomal dominant trait. martha has normal fingers and toes and normal color vision. her mother is normal in all respects, but her father is color blind and polydactylous. bill is color blind and polydactylous. his mother has normal color vision and normal fingers and toes. if bill and martha marry, what proportions of children with specific phenotypes would they be expected to produce? the answers only include the proportions of some of the possible phenotypes; other phenotypes are also expected to occur but are not included.