Oxygen because we need it to breath if that’s the wrong anwser sorry but it should be right
Phototropism plants the most
1) they have similar chemical properties.
for example fluorine from the 17th column is a non metal so does all the elements of that group.
2)they have same valence electrons in their outermost shell
example
electronic configuration of
hydrogen 1, lithium 2,1, sodium 2,8,1 and so on.
3) have same valency.
Its more natural and doesn't have side effects
el carbon es bueno para el atmosphere