I think it's the atoms/molecules that are constantly changing. They are slowly replaced... This is where your glial cells in your brain come in, they give nutrition to your neurons while slowly replacing all the molecules in each neuron one at a time. So on and so fourth for the rest of the body.

It's just like the lipids in all your cell membranes. If your body didn't cycle through nutrition, you'd never have to eat... That's why nutrition is so important, so that your body can efficiently and accurately replace these dying cells or just changing molecules. As for the lipids in cell membranes, this is the main reason why fat is required in everyone's diet... Intake of lipids, and carbohydrates among other molecules that make up cells are just as important as the water that you drink everyday.

So yes, I can believe this one.

However the other ones are BS, like the eye and legs... That's definitely not true, your legs use more ATP in their muscles just staying alive than your eyes do while moving.

Here are some fun facts though: with a proper diet, on average 70% of the calories you consume per day go to ATP and just keeping your cells functioning, that's not even including exercising.

Also if you multiply all of the possible neural connections in your brain, there are more POSSIBLE(not actual) connections within your brain than there are atoms in the entire universe. This is using the reasoning that one neuron on one side of your brain can connect with a neuron on the other side(not possible), so this is just taking all the neurons you have and multiplying them all together. Between two single neurons there are thousands of possible connections, so when you start taking 10 neurons the numbers are already huge, then add that to all the millions of neurons in your brain and it's more than there are atoms in the entire universe