Why do areas of high altitude (e. g., on the Tibetan plateau) have greater than expected UV intensity and areas of constant cloud cover (e. g., Congo Basin) have less than expected?

Explanation:

UV (ultraviolet) levels are high in the areas of high altitudes. Tibetan plateau being the highest plateau of the world is more exposed to the UV radiations as the atmosphere gets thinner in the areas of higher altitude. So it can not filter the maximum of ultraviolet radiations. Tibetan plateau is on 4,500 meters height and the UV level increase by 10-12% upon every 1000 meter elevation.

          However in those areas having the constant cloud cover like in Congo Basin the UV level is low as the clouds scatter the most of the UV radiations and they particularly stop the UV-B radiations. Thats why the cloudy areas have less UV level then the areas having a cloudless clear sky.

analyze the map below and answer the question that follows.

what does the map above tell us about the endemity of typhoid fever?

a.

there is greater occurrence of the disease in the western hemisphere.

b.

there is greater occurance of the disease in the northern hemisphere.

c.

countries located in equatorial regions are more likely to have incidents of typhoid fever.

d.

typhoid fever is more rampant among caucasian populations.