What is meant by resistance?

Three resistors $R_{1}$,$R_{2}$,and $R_{3}$ are connected in parallel between points $A$ and $B$. The equivalent resistance $R$ is given by:

Read the following statements carefully and state whether each statement is true or false:
$(i)$ The quantity of charge flowing past a point multiplied by time is current.
$(ii)$ The flow of charge through a conducting wire connected to a cell is the result of a chemical reaction inside the cell.
$(iii)$ The resistivity of all pure metals increases with an increase in temperature.
$(iv)$ Ohm's law is a relation between the power used in a circuit to the current and the potential difference.
$(v)$ $A$ series circuit has only one conducting path for the electrons that move through it; a parallel circuit has multiple conducting paths.
$(vi)$ $A$ conducting wire offers resistance to the flow of electrons because electrons repel each other in the wire.

Give two practical applications of the heating effect of current.

What is the unit of electric current?

What type of electric charge does an electron possess?