Which statement best describes cancer cells? They grow as a single layer of cells. They cease to reproduce after 20–50 mitotic divisions. They reproduce only when needed to replace missing cells. They are not regulated by contact inhibition.

all matter is made up of atoms

in any element all atoms are the same

elements in a compound are always in a constant ratio: apex

this age may represent the age of the earth's accretion, of core formation, or of the material from which the earth formed. this dating is based on evidence from radiometric age-dating of meteorite material and is consistent with the radiometric ages of the oldest-known terrestrial and lunar samples.