What is the definition of microorganism

_tissues respond quickly to outside stimuli a) epithelia b)nervous c)muscular d)muscular and nervous

Scientists discovered fossils in several layers of the earth you see here. they found fossils of algae, snails, and clams in layer d. given that information, where do you think they found fossil evidence of simple land plants and amphibians?

Restriction enzymes are used in making recombinant dna. describe the role restriction enzymes perform when constructing recombinant dna