Which scientist studied how wounds healed and proposed that cells came from preexisting cells?

Which potential solution below best addresses the issue of loss of biodiversity in a north american ecosystem?

The distant ancestors of tigers may have had bodies without stripes. use the theory of natural selection to explain how tigers may have evolved to have stripes.

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