I think it is Ag and Au but not two sure
Their valency is one and both belong to the third period
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>
D it causes lava to rush out faster