Tornadoes often form after_

is not the pressure change. The air pressure will drop near a tornado. Many people near a tornado tell of their ears "popping" due to the pressure change.

hope this helps. I didn't really understand this.

sonar maybe? ? i dont know the choices

  the common sense as a pamphlet written by thomas paine. it promoted the independence of the colonies from british rule. the distribution of this pamphlet was great, it reached people everywhere and it was even read aloud at places people met. it also unite the colonists before the revolutionary war.

answer is d