Assertion (A): Higher the range, lower is the resistance of an ammeter
Reason (R): To increase the range of an ammeter additional shunt is added in series to it

Explanation: Ammeter's resistance should be low as much as possible and it is connected in series in a circuit so total resistance of circuit should not be affected.

If we want to increase range of ammeter, we have to decrease the resistance which is possible by adding a shunt in parallel to it.