The horse and donkey, though closely related by sharing a common ancestor, are different species. They have different number of chromosomes hence pairing of homologous chromosomes during fusion of gametes becomes complicated. The mule will have an extra chromosome from the horse hence will have abnormalities such as sterility. A Mule is unable to reproduce due to this same phenomenon. Homologous chromosomes are not well paired for meiosis I.
After the star's outer layers are expelled, the density of the remaining material is typically too low to provide adequate energy to sustain the hydrogen-burning shell's nuclear temperatures, and the remaining star easily contracts to form a white dwarf (a star with a density equal to the Sun, but a diameter equal to the Sun).
Answer:the color explanes it's self old and young
Explanation:
<span>Chronic stress that weakens systems in the body.</span>