Answer: 0.69 m/ mile.
Explanation:
The altitude gradient between two cities X and Y = 
Given: Two cities are separated by 200 miles.
City X has an altitude of 122 meters.
City Y has an altitude of 260 meters.
The altitude gradient between two cities X and Y =

Hence, the altitude gradient between the two cites = 0.69 m/ mile.
<span>C. metric ruler since millimeters are metric</span>
<span>It is going to depend on what you consider stable. A
diverse population would be more resistant to disease because of simple
biology. The more sources for possible resistance the better the
heterogeneous pool will be at resisting disease. You also have to take
in to consideration things like the availability of modern medicine and
the ability to be isolated during illness. </span><span>
Personally I think it has to do with the fact that many of the worlds
more diverse population centers are also many of the worlds largest
population centers which make them less prone to invasion on that basis
alone. </span>
The answer for the first question is
1. 5ml
The answer for the second question is
2. 4g/ml