What is a protozoan? how is a protozoan parasite different from bacteria and multi-celled -parasites such as intestinal worms

Name one similarity and one difference between the morphology of a brachiopod and a bivalve

Plz ! ive been stuck on this forever

Which statement describes how favorable traits in a population relate to natural selection? they are the only traits that ever exist in the population. they build in the population over time. they are rarely passed on to offspring. they are found only in a few individuals within the population.