You can, for instance, observe the cells, hear your heartbeat, watch your skeleton cycling and measure how much air you have in your lungs. Measure how much air you breathe in and out with each breath. Ride the bike and see how long it takes to burn enough calories for a tomato or a beer. It will reveal how much air you breathe in and out with each breath. Try to answer honestly, based on your opinion.
Most smells seem familiar but are still difficult to recognize.
The TV monitor shows the chicken egg that's under the microscope. The egg was fertilized about 72 hrs. You can already see the heart beat. Sit down and close your eyes. This plastic model shows where various organs are in the body.