<span>b.internal fertilization
</span>Sexual reproduction provides genetic variation because the sperm and egg that are produced contain different combinations of genes than the parent organism. Sexual reproduction involves meiosis which is the process of a cell doubling its DNA, shuffling its genes and then dividing the shuffled DNA among four cells.<span>Each resulting cell, or gamete from meiosis has only half the amount of DNA as the parent cell. So in order to form a new organism, two gametes, sperm and egg, must fuse, further mixing the genes to produce more genetic variation.</span>
Answer: A.
Explanation:
The secondary growth of a plant happens in the vascular cambium. When the vascular cambium produces more tissues, it makes the stems thicker over time.
It is caused by the atmosphere of the Earth. It is due of the scattering of light by the atmosphere. When the moon is near the horizon, the moonlight must pass through much more atmosphere than when the moon is directly overhead.