It is known that all the stars of a particular open or globular cluster are of the same age. Why then do these stars fall

It is known that all the stars of a particular open or globular cluster are of the same age. Why then do these stars fall into different places on the Spectrum-Luminosity diagram?

Stars have different masses, which determines different luminosities and different rates of evolution.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.