Imagine looking through a microscope at a squashed onion root tip. the chromosomes of many of the cells are plainly visible. in some cells, replicated chromosomes are aligned along the center (equator) of the cell. these particular cells are in which stage of mitosis?

Metaphase.

Explanation:

Metaphase may be defined as the stage of the cell cycle followed after the prophase and before the anaphase. The chromosomes are joined together with the centromere.

This stage can easily be identified in the microscope. The chromosomes are aligned themselves at metaphasal plate in the center of the cell.

Thus, the answer is metaphase.

the relative atomic mass of an element is the mass of one atom of that element, relative to 1/12th of the mass of a  1212c atom. to convert to an absolute mass in kg, it is necessary to multiply by  1.661×10−271.661×10−27.

the relative atomic mass is roughly equal to the number of neutrons, plus the number of protons, in the nucleus of the atom.

for elements with more than one stable isotope (different types of nucleus with different numbers of neutrons but the same number of protons), the quoted mass is usually the average mass, weighted by the relative abundance of the different isotopes.