The image given for this question is drawn exactly as it appears in the JAA Airframe System 021 examination.

You are told in the question that the image represents a type of gas turbine engine.

You can see that there are two shafts in the image yet they are clearly not connected to each other.

The two vertical oblongs at the ends of the shafts represent turbines.

This would indicate that this is a Free Power Turbine Engine.

The triangle shaped section drawn at the left represents a centrifugal compressor.

It is a basic diagram we agree, this image is based on the PT6 engine, you may wish to look at cut away diagrams of the actual engine on the net.

We think you will then see why the JAA use such a simple diagram for the examinations.