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.
An isometric exercise is a form of exercise involving the static contraction of a muscle without any visible movement in the angle of the joint.
Answer:
MRI = Electromagnet
Moon = Not magnetic
Compass = Permanent magnet
Chemotherapy is a process of intense treatment for cancer. It includes one or more anti-cancer drugs. However, most people become sick after they go through with chemotherapy. This can last for days or longer. Hopefully, nobody gets cancer and has to go through this procedure.