A star's energy comes from combining light elements into heavier elements in a process known as fusion, or "nuclear burning". It is generally believed that most of the elements in the universe heavier than helium were created in stars when lighter nuclei fuse to make heavier nuclei.
A star's energy comes from combining light elements into heavier elements in a process known as fusion, or "nuclear burning". It is generally believed that most of the elements in the universe heavier than helium were created in stars when lighter nuclei fuse to make heavier nuclei.
Habitat isolation is a mechanism that prevents species from mating even if they don't have reproductive barriers. The differences in the habitat types may thus be sufficient to develop reproductive isolation between two (or more) populations
