I would select B or C as the answer because i have no idea what the other ones are :)
The answer is it provides us with vitamins. Hope this helps.
In frogs, different mating seasons are a barrier to reproduction.
Answer: Well, populations never evolved than one human might have gone extinct due to many different viruses and sicknesses but other animals might not be extinct. If populations never grew more then that would be because we could not overpower dome viruses. If we never. If we never evolved animals like a Carrier pigeon would not be dead or extinct today.
Your question does not make sense
