Answer:
Sexual reproduction
Explanation:
There are two asexual so I'm going to assume you meant sexual because the rest of these answers create identical offspring.
Remember that sexual reproduction is how humans are made and we are very different from our parents!
B, 30% billion, because there are 8 billion people on earth and that answer makes the most logical sense
I think the answer is c because the cooler summers help cool down the earth preventing global warming