Human reproduction<span> takes place as internal fertilisation by sexual intercourse. During this </span>process<span>, the male inserts his penis, which needs to be erect, into the female's vagina, and then either partner initiates rhythmic pelvic thrusts until the male ejaculates semen, which contains sperm, into the vaginal canal.</span>
<span>Messenger RNA (mRNA) is known
to be molecules that carries codes (DNA) in the nucleus to the cytoplasm the
sites of protein synthesis. Thus, it is the RNA copy from one section of the
DNA that usually correspond to a single
gene. </span>
The reason that the answer is 1/4 is because the young man, his grandfather, his father, and his mother equal 4 people. The young man is 1 person. 1 person/4 people = 1/4.