1. for most of the 17 years in which he was active, the identity of the unabomber remained a mystery.

true false

2. polygraph machines measure physical changes in the body when the individual is asked 'yes' and 'no' questions.

true
false

3.false positives occur when the examinee tells the truth but his response is recorded as a lie.

true
false

Answer  they are all true.

Explanation:

The Unabomber had no identity until he finally confessed in 1998. Therefore, the answer is true, (its almost like a trick question.)

The Polygraph machine does measure physical changes in the body, so the answer is true.

False positives are when the examinee tells a truth but it is recorded as a lie.

the cold front replaces the warmer air at the ground level changing the wind to be breezy and denser.there is also an immediate drop in the temperature.