Easy. Answer is oxygen because it says which one was missing before any life was on earth. And in order to have life on earth you need oxygen!
:)
Answer:
Lymphocyte ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎
︎
︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎
︎
︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎
it is grasshopper because they donot have backbones
Northern hemisphere : Summer because it is tilted towards the sun.
Southern Hemisphere : Winter because it is tilted away from the sun.