Can energy disappear?

It is true that energy cannot be created or destroyed. Let's look at some things that state that.

The Law of Conservation:

The Law of Conservation by Newton states that energy can't be created nor destroyed, just changed. You see, there are different types of energy. Electromagnetic energy, mechanical energy, chemical energy, and heat energy is just a few.

Changing Energy:

When your body runs a mile, like you stated, does not lose energy. Here, let's go back to what you ate. Say, that you ate salad before the race. First off, electromagnetic energy radiates off the the plant. Then, the plant changes it into chemical energy for food. Next, you come along to eat it, keeping it in chemical. When you run, it makes it mechanical energy so you can use it. It is the same with moving an object.

Matter:

Matter cannot be created or destroyed either. Matter is space.

Growing:

Growing is losing things then gaining them. For example, look at cells. When they die, they reproduce more.

Energy never destroy. But it help us to do work by converting.

In matter this system also applicable. It only convert into another one by action or reaction. One the other hand organisms are grown by using energy.

According to theory, energy and matter are conserved. When you exercise, or when a machine is running, all of the energy produced is ultimately converted to heat which is conducted into the Earth's atmosphere and into the Earth itself. The heat of the Earth is radiated in all directions through space, where it may be reabsorbed by another massive body. All of the Earth's energy comes from the sun and from the residual heat in the Earth's core which is mostly heat left over from the Earth's creation. Organisms utilize this energy and the hydrologic cycle and dynamic processes in the Earth's atmosphere are driven by these energies. Organisms and the dynamic processes of the Earth ultimately release all of the energy that was absorbed back into the environment.

Organisms grow by consuming atmospheric gasses and organic and mineral nutrients of or on the Earth. These nutrients are converted in new cells, allowing the organism to grow and reproduce. When an organism dies, bacteria and other organisms consume the dying and dead cellular tissues.

Energy is released as heat 10%

it turn to the heat.