Why are the oldest parts of the ocean floor no more than about 200 million old?

Because they are renewed.

Explanation:

Oceanic crusts are usually renewed in the Earth's mantle relatively quickly in subduction zones (where tectonic plates collide with each other) due to their high density, and are less than 200 million years old.

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.