What is the relationship between malaria and sickle cell anemia?

Which of the following is a period in the paleozoic era? devonian cambrian permian all of the above

Which of the following factors would not contribute to allopatric speciation? a) a population becomes geographically isolated from the parent population.b) the separated population is small, and genetic drift occurs.c) the isolated population is exposed to different selection pressures than the ancestral population.d) different mutations begin to distinguish the gene pools of the separated populations.e) gene flow between the two populations is extensive.

Modern sea star larvae resemble some primitive vertebrate larvae. this similarity may suggest that primitive vertebrates