By 1949 americans who lived within the range of a television stations in the country could watch tv, vastly changing the way that humans communicated with each other. what type of electromagnetic wave made tv technology possible?

Microwaves.

Explanation: First, we have a trivial answer, and that is the visible light, which is responsible to let the information on the tv to be seen by the user.

Now, TV technology was possible thanks to the microwaves, that are used because these can carry more energy than other types, and these microwaves needed a special technology because they couldn't be handled by the current technology at the time.

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.

b. a lightning bug, plug of grass, and a worm