Can inserting a resistor in a circuits have an effect similar to an open circuits?

Question

circuits laboratory

Answer 1

a high resistance could be "similar" to an open circuit, particularly in a low impedance circuit.

For example a mega ohm resistor in series with an electric hairdryer will act like an open, but in series with the gate of a FET not so much.

Answer 2

An open circuit is equal to having a resistor of infinite resistance  inside the circuit.  So, pick a very high resistance to imitate an open circuit.

A closed (short) circuit, on the other hand, is like having a resistor with 0 resistance.