Look at the circuit diagram. which of these components is part of the circuit

You have not provided choices, therefore, I can not provide an exact choice.

However, I will tell you the components of the given circuit and you can choose the one found in the choices you have.

The given circuit is composed of:
1- A battery:
It has the symbol of the long line and short line next to each other. The long line represents the positive pole while the short line represents the negative one. Battery is used to supply power to the circuit
2- An ammeter:
If has the symbol of an "A" in a circle. This device is used to measure the current flowing in the circuit
3- A resistance:
It has the symbol of the zigzag line. Resistance could be any device that consumes the power in the circuit.
4- A switch:
This has the symbol of the line at the bottom of the circuit. In its current status, the switch is off which means that no current is flowing in the circuit. If we connect the open terminal of the switch with the circuit, the switch is said to be on and current would flow in the circuit.

Hope this helps :)