Which best compares ac and dc?

ac flows in one direction, and dc repeatedly switches direction.
dc flows in one direction, and ac repeatedly switches direction
ac is used only in generators, and dc is used only in motors
dc is used only in generators, and ac is used only in motors

DC flows in one direction, and AC repeatedly switches direction

Explanation:

DC stands for direct current.

AC stands for alternating current.

When current flows only in single direction, it is known as direct current. When current changes direction i.e. it alternates direction, it is known as alternating current.

There are both AC generators and DC generators.

AC generators supply power to home appliances and small motors. DC generators are used to power large electric motors.

falling water hydro = water .. spectcular places these plants are

the total distance traveled by the car is

30km + 49km = 79 km .