Out of ammeter, milliammeter and microammeter which one will have lowest resistance and why?

Problem : Out of ammeter, milliammeter and microammeter which one will have lowest resistance and why?

Doubt by Aryan 

Solution : 

We know, the value of shunt resistance required to convert the given galvanometer in ammeter is given by 
S=I_gG/(I-I_g)

Clearly 
S∝1/(I-I_g)
I_ammeter>I_milliammeter>I_microammeter
So
S_ammeter<_{Smilliammeter}<_{Smicroammeter}

In parallel combination the equivalent resistance is always less than the samllest individual resistance. So,
R_ammeter<_{Rmilliammeter}<R_microammeter

Hence, If ammeter, milliammeter and microammeter are all made from the same galvanometer then the resistance of ammeter will be the lowest.