Natural selection could not occur without:
a. genetic variation in species
b. environmental changes
c. competition for unlimited resources
d. gradual warming of the earth

How does natural selection change thephenotypes within a population over time?

How are the reproductive cycles of a fungus and a pteridophyte similar? a)both organisms form fruiting bodies that produce diploid seeds. b)both organisms produce haploid spores and exhibit diploid and haploid stages. c)both organisms reproduce sexually when two haploid hyphae fuse. d)both organisms exhibit a diploid stage and are only able to reproduce asexually.

What is the membrane that sheath of schwann cell containing cytoplasm and nucleus that encloses myelin