The regulatory centers for the respiratory and circulatory systems are found in the cerebrum
Answer: D. Keratin
Explanation: Keratinocytes (pronounced: ker-uh-TIH-no-sites) make keratin, a type of protein that's a basic component of hair, skin, and nails. Keratin in the skin's outer layer helps create a protective barrier.
According to ChaCha.com, "Parthenogenesis is a form of agamogenesis in which an unfertilized egg develops into a new individual. Parthenogenesis occurs naturally in many plants and invertebrates. This differs from other forms of asexual reproduction because an egg is used."
The Answer Is A. Hope This Helps ;P