The layer of a star is very dense and hot, while the layer of a star is much cooler and less dense.
The layer of a star that is very dense and hot is known as the core. The core is the central region of the star where nuclear fusion reactions take place, generating immense heat and pressure. These reactions convert hydrogen into helium and release a tremendous amount of energy in the form of light and heat.
On the other hand, the outer layer of a star, called the photosphere, is much cooler and less dense compared to the core. The photosphere is the visible surface of the star that emits the majority of its light and heat. It is relatively thin compared to the rest of the star and has a temperature that can range from a few thousand to several tens of thousand degrees Kelvin, depending on the type and size of the star.
The temperature and density decrease as we move away from the core towards the outer layers of a star. This is why the core is the hottest and densest region, while the outer layers, such as the photosphere, are cooler and less dense.