The Earth was first considered habitable when we discovered that it was Microbial organisms that started the process. I would go with D.
Answer:
Destruction of habitats, Introduction of non-native species, pollutions, and the over harvesting of species.
False. Strontium 90 has a half life of only 30 years, and as millions of years pass, about the time fossils have been around, most if not all of any strontium would have decayed.
They form a structure of zygote
