Answer:
Oxygen levels stay above 15 percent starting 200 million years ago
Explanation:
Atmospheric oxygen levels are related to the evolution on Earth and changes in geochemical cycles that involve climate variations.
The presence of O
2 and evolution of oxygen gave new opportunities to the life on Earth. Oxygen levels in atmosphere have fluctuated between 15% and 35% of atmospheric volume, since the start of the Cambrian period.
So, form the starting 200 million years ago, oxygen level stay above 15 percent and the correct option is "B".
It’s z cuz y=mxtb and u solve the parobola and its 11teen
Answer:B antvenin as is always specific
Explanation:othe like antigen are for antibodies snake venom is just venom while penicillin is from fung
Chemical properties? raft? 2 different realms my friend