If the earth's differentiation were any different, its gravitational pull and might have been affected. options
temperature
tectonic activity
heat transfer

Which element is used in photosynthesis found in atmosphere and fixed by bacteria?

What does polymerase chain reaction (pcr) do? o a. separates dna fragments by size o b. cuts a dna sample into fragments o c. provides an overall picture of a person's chromosomes o d. makes more copies of a sample of dna

Which kind of worm has a closed circulatory system? a planarian b fluke c pinworm d an earthworm