Crossing over? That involves the random exchange of chromosomes.
Answer:
The two components are often found as part of an enzyme are: Protein: proteins increase the rate of reaction that takes place within the living organism. proteins consist of one or more chains of amino acids that make macromolecules.
Explanation:
B - They both use protein channels (I think so at least) they differ because active transports use a pump to leave the cell and it uses atp (cell energy).
One explanation could be the differences in climate (environmental factors). The climate in northern Mexico could support the reproduction of the mosquito species, which is a vector of the dengue virus. Other environmental conditions that influence its endemicity could include living conditions and sanitation. The other possiblity could be that the people in the US have developed immunity for the disease, therefore, are unaffected even when infected by the virus.