Prostate gland
Seminal fluid being alkaline helps to neutralize the acidic environment of the vagina, which could otherwise be harmful to sperm. This alkalinity supports the survival and motility of sperm, increasing the chances of successful fertilization.
Bulbourethral glands
Sebum
This substance is called melanin.
mucus
Enamel.
retinol
mucus
A lining made of mucus.
Melanin is a substance produced by the skin that protects the skin from ultraviolet radiation. It also gives skin its color.
the cytoplasm is a jelly like substance that protects the organelles in the cell
Nacre