A human cell with an unknown type has 23 chromosomes. Which of the following types of cells can the unknown be? Skin cell
Sperm cell
Cardiac cell
Intestinal cell

What is the problem in this article? what solution does the article propose?

In many humans, exposing the skin to sunlight over prolonged periods of time results in the production of more pigment by the skin cells (tanning). this change in skin color provides evidence that -

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