Explain briefly why you cannot expect to find a previous version of every file with which you work.

Which of the following is a way that advancements in technology improve humans' ability to measure air quality and protect human health? a. air quality data gathered by new instruments can be used to reduce exposure to pollutants. b. new technologies enable natural and human-made pollution sources to be located and monitored. c. air quality data gathered by new instruments can be used to predict trends in pollution over time. d. new technologies allow governments to make informed decisions about the regulation of pollution. (choose more than one)

Suppose an astronomer discovers a large, spherical-shaped body orbiting the sun. the body is composed mostly of rock, and there are no other bodies sharing its orbit. what is the best way to categorize this body? a. planet b. moon c. comet d. asteroid

Are special combinations of keys that tell a computer to perform a command. keypads multi-keys combinations shortcuts