Air becomes wind as it flows from
a. low pressure to low pressure.
c. low pressure to high pressure.
b. high pressure to high pressure.
d. high pressure to low pressure.

correct answer is option d (high pressure to low pressure.)

Explanation:

Air:

Air is the mixture of  various gases like oxygen, carbon dioxide and nitrogen. These mixture of gases are present in the atmosphere.

Wind

When air started moving in horizontal direction due to pressure difference between two points. When air flows from high pressure to low pressure area  it became wind. Wind has both direction and speed.

Therefore air becomes wind as it flows from high pressure to low pressure

the total distance that martina travels that day is

(distance from home to mom's office) plus (distance from mom's office to school)

plus (distance from school to library) plus (distance from library to friend's house)

plus (distance from friend's house to martina's house).

(we don't know what any of these distance actually is.)