What is the definition of parameter?
Which type of context clue is used in the sentence?

The difinition of Parameter is A parameter is a limit. In mathematics a parameter is a constant in an equation, but parameter isn't just for math anymore: now any system can have parameters that define its operation. You can set parameters for your class debate.

Explanation:

answer; (b); the abolitionist movement;

the direction of the magnetic field produced by an electric current will change when the direction of the electric current changes. for example : if a current is flowing in a straight length of wire, the magnetic field is described by a concentric circle (using right-hand rule).