abstract: Based on a newly proposed mirror-matter model of neutron-mirror neutron (\(n-n’\)) oscillations, evolution and nucleosynthesis in single stars under a new theory is presented. The new theory with the new \(n-n’\) model can demonstrate the evolution in a much more convincing way than the conventional belief. In particular, many observations in stars show strong support for the new theory and the new \(n-n’\) model. For example, progenitor mass limits and structures for white dwarfs and neutron stars, two different types of core collapse supernovae (II-P and II-L), synthesis of heavy elements, pulsating phenomena in stars, etc, can all be easily and naturally explained under the new theory.