In a living organism, what is an organ?
functional unit, or building block, of all organisms; smallest unit that can carry on the activities of life
the shell or skin of an organism
a structure composed of a number of tissues that work together to perform a specific task
a group of similar cells that perform a common function

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.

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

the titanic would be the correct answer