Answer:
D. tip his head back farther to open his airway.
Explanation:
Tilting the head farther back moves the tongue away from the back of the throat, allowing air to enter the lungs.
Answer: genetic variation
Diploid cells are like daughter cells coming from a mother cell called a haploid cell. So the more daughter cells are born, the greater the chance of getting hybrids and creating more diversity on the genetic races existing. In this case, the answer would have to be honeybees.