When males reach a certain age, the body begins the process of puberty. how does the body control this process?

In girls, the main hormone that starts to be highly expressed is estrogen and progesterone while in males, testosterone. This is triggered by the hypothalamus that releases gonadotrophic-releasing hormones (GnRH).  GnRH then triggers the pituitary to release LH (Luteinizing Hormone ) and FSH (Follicle Stimulating Hormone) that act on the gonads (ovaries in females and testis in male)

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds