One of the advantages of alternating current (ac) over direct current (dc) is the ease with which voltage levels can be increased or decreased. a. True
b. False

True

Explanation:

In an alternating current, voltage levels can be easily increased or decreased as per the requirements of the energy distribution in practical world.

Hence, the given statement is true

answer: the correct answer is   air pressure at the top of mount everest is higher than at the bottom of the grand canyon.

hope this : )

explanation:

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.