Describe the differences between a chromosome and a dna molecule

A chromosome is made of both one DNA molecule wound around small protein molecules where DNA is just one large molecule called deoxyribose nucleic acid.

Each chromosome has two molecules of DNA. DNA is the chemical form which stores genetic information and a chromosome is the highest organized structure of DNA double helix with proteins.

it's c. (to reduce the greenhouse effect/carbon gasses)

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.