Answer:
335 million years ago
Explanation:
Pangaea or Pangea ( /pænˈdʒiːə/) was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from earlier continental units approximately 335 million years ago, and began to break apart about 175 million years ago.
I believe they cannot start with big trees and bushes because the there is not enough nutrients in the soil, so instead pioneer species pave the way for primary succession.
A. temperature and salinity
Answer:
the procedure aims to replace the stem cells in the bone marrow the source of new red blood cells with healthy stem cells from a matching donor
