For example, in a person on the x chromosome, a dominant gene (H) is located that determines normal blood coagulation. A recessive version of this gene (h) leads to a decrease in blood coagulability called hemophilia. The Y chromosome does not have a pair that is alley to this gene, and the trait (blood clotting) appears in men even though the h gene is recessive.
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.