What prevents a lake or ocean from freezing solid?

Which of the following is true of microbes? a. ninety-nine percent of all microbes are pathogenic.b. gene expression in bacteria is very similar to gene expression in humans, which facilitates the use of bacteria in recombinant biotechnology and gene therapy.c. all bacterial enzymes are harmful to humans and the environment.d. microbes create pollutants and toxins that harm the environment.

Cell specialization occurs by the process ofa. reproductionb. differentiationc. maturationd. growth

What was the land like over 500 million years ago? what was under the sea?