Show Me, Tell Me: Brake Fluid

"Tell me how you'd check that you have a safe level of hydraulic brake fluid."

When you depress the brake pedal, it pushes oil through thin pipes, which activates the brake shoes or discs, depending on the type of brakes your car has. If the level of this oil, or brake fluid, gets low, air bubbles could get into it, which would cause the fluid to become more elastic and make the brakes less effective; they could even fail completely.

With the bonnet open, look for the brake fluid reservoir. The cap usually has yellow imagery and writing on it, and will be something like this:

This is the one in the Peugeot; there are other fluid reservoir bottles in the engine compartment; it is important to select the right one. It has symbols on it; the first one is:

The octagonal shape refers to a stop sign; the symbol inside is intended to show brake pads clamping onto a cylinder. The next one is:

A warning triangle, telling you to take care, and ...

... read the book, referring you to the car's manufacturer's guide. This will tell you that you should only remove the cap in a dust-free place, and that you should use the correct grade of brake fluid:

There are broadly two types of brake fluid, glycol based or silicon based. Most cars use DOT 4, which is glycol, but check either on the cap, or in the manual, that you are using the correct one. The two CANNOT be mixed. An alternative style of filler cap could look like this:

It still has the octagonal 'brakes' symbol, with written instructions.

The sides of the reservoir should be transparent enough that you can see the fluid level, and it should be between the maximum and minimum markings:

Your answer to the question is that you open the bonnet, point at the brake fluid reservoir, and state that it should be between maximum and minimum.