The Sun is the closest star to our planet. The Sun is our primary energy source, which manifests itself with light and huge amounts of heat.

A galaxy is a vast collection of stars, gas, stardust, [...]

The environment is the group of natural and artificial elements that make possible the presence of human beings and other organisms in a given space and time.

The cell is the most important element and fundamental unit of living [...]

The term proton comes from the Greek prōton, which means first. It [...]

Electrons are subatomic elements and the lightest essential particles that make up an atom with the least negative electrical charge.

An endothermic reaction absorbs energy, in the form of heat or radiation, from its surroundings to take place.

Exothermic reactions are chemical reactions in which heat is released. They are produced due to the energy of the molecules.

Simple machines have few or no moving parts. They make [...]

A gear is a set of toothed wheels that work [...]