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.
Answer: A
Explanation:
Karyotypes can be used to screen for and confirm chromosomal abnormalities such as Down's syndrome, and there are several different types of abnormalities which may be detected.
Some arteries carry oxygenated blood just as some capillaries do.
Some veins carry deoxygenated blood just like some capillaries do.
It can be between restaurants to see who is better at serving and service or a competition between 2 or more people at an activity.
