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.
Answer:
Mechanical barriers — which include the skin , mucous membranes , and fluids such as tears and urine — physically block pathogens from entering the body. Chemical barriers — such as enzymes in sweat , saliva , and semen — kill pathogens on body surfaces.
A. Heat will not flow because there is no temperature difference between the substances.
In humans, one feedback mechanism is to either sweat or shiver, depending on the body temperature. Sweating helps lower the body's temperature, and shivering helps raise the body's temperature.
Answer:Rhythm
Explanation:
This is because rhythms are repetitive, cyclical patterns of behavior generally. For example waking, eating are examples of rhythm for a baby.