The resistance and inductive reactance of an ammeter must be very low. The ammeter has a very reduced impedance because the voltage drop around across the ammeter should have been minimal.
The ammeter cannot be attached or linked in parallel for the reasons stated above. The current will be the same across a series connection.
Connecting an ammeter throughout parallel can also cause a short circuit, and the current going through the ammeter can burn the instrument. The impedance of an ideal ammeter must be zero throughout in order for the power loss around across the apparatus to be zero.
