Which best describes the differences? (PLEASE ANSWER ASAP!! I WILL AWARD BRAINLIEST) (image below) 1. The cactuses in 1970 had smaller spines than the cactuses in 2015.

2. The cactuses in 1970 had larger spines than the cactuses in 2015.

3. There were more cactuses in 1970 than there were in 2015.

4. There was more variation in spine size in 1970 than there was in 2015.

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.

organ system-an organ system is a group of organs that work together to perform one or more functions. each does a particular job in the body, and is made up of certain tissues.