What 2 characteristics are used to place organisms into different kingdoms

One of the characteristics used to place organisms into kingdoms is their ability to make food. Other characteristics used are the cell structure that is whether prokaryote or eukaryote, absence or presence of cell wall, presence or absence of other organelles, cellularity may also be used such as whether unicellular or multicellular, and lastly the mode of nutrition such as whether heterotrophs or autotrophs, e.t.c

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.

i think its the first one