The greater amount of eumelanin in darker skin protects folate from being broken down by UV radiation and thus increases fitness among populations in high-intensity UV areas. ... However, it does not explain why there is variation in human skin color.
Selectively permeable means that cells only allow certain molecules to enter or exit a cell.
Limiting factors are resources or other factors in the environment that can lower the population growth rate. Limiting factors include a low food supply and lack of space. Limiting factors can lower birth rates, increase death rates, or lead to emigration.
Answer:
Disease spread can affect air travel really badly because it can be so easy for anyone to get infected with how crowded airports can be. This usually results in extra safety steps taken up to cancelled flights due to closed borders. A popular example of this is the current pandemic crisis.
Explanation:
The Taxonomic rank ( from the largest to the smallest) goes something like this:
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
So, the largest from your given options is phylum.
Hope this answered your question