I would say a beacause tundra is very cold desert snd only certain amount of vegetation can happen
The mass of an atom is contained primarily in its NUCLEUS.
An atom is made up of three sub particles, which are proton, neutrons and electrons. The proton and the neutrons are located in the nucleus of the atom while the electron are located outside the nucleus where they move about in continuous motion around the nucleus. The proton and the neutrons, which are located in the nucleus have the same relative mass of 1, which has been estimated to be about 2,000 times bigger than that of the electron, which has a relative mass of 0.0005. This shows that, the mass of an atom is located primarily in its nucleus. <span />
I think but I do not know it refered to as being repetitive
For giving you understanding ; we need Free O2 but Oxygen is also available in H20 right why dont we use it !!
As the early atmosphere was reducing as there was no free oxygen but it was later produced by chemoautotrophic bacteria !! Living thing release O2 in atmosphere thus making it oxidising in nature and then life evolves !!
