- A star produces light and heat
- A source of something emits / produces / generates / provides that something
- Therefore, a star is a source of light

- A star is a source of light
- As the size of a light source increases , that light will appear brighter
- Therefore, as the size of the star increases, the light will appear brighter

Therefore, as the size of the star increases, the light will appear brighter
Question: An astronomer is studying two stars that are the same distance from Earth. Star X appears brighter than star Y. Which statement best explains this observation?
Context: - As the size of a light source increases , that light will appear brighter 
- A star produces light and heat 
- A source of something emits / produces / generates / provides that something