I personally think that it's D. If this is right you're welcome. If it's wrong feel free to delete this answer :p
The allele for sickle cell anemia would be an example of natural selection. In most situations, having crescent shaped red blood cells would hold less oxygen & would not be ideal. But in places that are affected by diseases like malaria, which attack red blood cells, having crescent blood cells minimizes the threat malaria can cause.
Hope this helps!
Tundra plants, blueberries, and birch.
Answer: C. Vascular tissues, which conduct water and nutrients against the pull of gravity.
Explanation:
Because Moss and other bryophytes lack vascular tissue and sharing a number of other primitive traits.