Answer:
A. the frequency will decrease because all mutations are harmful, thus People with the mutation will die.
So it's going to be obviously oxygen XD ....so that's one
Next, it's going to be carbon dioxide, since it has to exit the cell, because it is a waste product ...so that's two
Finally, it's also going to be something you drink everyday.
*whispers* it's water XD because of osmosis
So recap:
1) Oxygen 2) Carbon Dioxide 3) Water
hope that helps!! :D
During meiosis, the 2 alleles for each gene stay together.