There can be a lot of factors that express sexuality. The origin would be its genes. The genetic make-up of the person what trait has passed on to an individual from his parents. Another factor is the environment. A person's sexuality can be influenced by social groups, home environment and from the media that he/she looks at.
the RBC first is in the arteries then it reaches the body cells via the capillaries then the deoxygenated rbc reaches the heart through veins which carry those
