Class c helmets are made of aluminum and do not provide protection from:
a. electrical hazards.
b. impact hazards.
c. penetration hazards.
d. all of the above.

Ahypothesis is? close agreement by competent observers of observations of the same phenomena. a guess that has been tested over and over again and always found to be true. an educated guess that has yet to be proven by experiment. the long side of a right triangle. a synthesis of a large collection of information that includes guesses.