Because the gene for the O blood type is common within in the gene pool.
It doesn't matter whether the gene is dominant or recessive, it matters on how on that ^
Upwelling is a process in which cold water from depths arise to the surface,
it's important because :
- It bring a lot of nutrients to the surface of the ocean
- It maintain the temperature of the ocean
hope this helps
I think the answer is B because it happens slowly and through natural selection