Answer:
7.8 Billion, but to round it...t is 8 Billion
Explanation:
This is the question to search up. I don't think anyone but the internet knows how many people exist...if you understand.
Answer: Well really the digestive, respiratory and circulatory systems all work together to make cellular respiration possible so i guess you could choose a or b
Explanation:
Okay, this has to be in your own words, but I will tell you this. Natural Selection is living organisms that have adapted to the environment which surrounds them leading the the producing of offspring. Example, bugs are eaten by frogs and frogs are eaten by snakes and snakes are eaten by birds.
<span />
It might be an astrocyte, but I'm not sure.
