The largest aperture telescopes are reflectors because they require a focal length.

longer
shorter

Which safety measures should you follow during a thunderstorm? check all that apply. (a) avoid touching anything that conducts electricity. (b) avoid touching a person who has been struck by lightning. (c) go outside. (d) keep your computer turned off. (e) stay out of water. (f) stay inside.

Several mountains together form a mountain . a few of these combined form a mountain system. several systems combined form a mountain , which can stretch thousands of miles in length.

Apersons beliefs and general outlook, which act like filters on the information they receive are called ?