How the kidneys filter wastes from the blood?

Each of your kidneys is made up of about a million filtering units called nephrons.

Each nephron includes a filter,

called the glomerulus, and a tubule. The nephrons work through a two-step process:

the glomerulus filters your blood,

and the tubule returns needed substances to your blood and removes wastes

"record the time to complete a chemical reaction" would most likely be part of a lab procedure.