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:
The two hydrogen atoms and one oxygen atom within water molecules (H2O) form polar covalent bonds. ... As a result of water's polarity, each water molecule attracts other water molecules because of the opposite charges between them, forming hydrogen bonds
<span>The challenge of reproducing is one of important manners which distinguishes migratory birds from another birds. The question is that which examples descrbe such manners, and for that, we can choose A, C and D</span>
B) the less porous, the less permeable
Porous means "full of holes."
Permeable means "stuff can go through it."
The more porous something is, the more permeable it is.