The correct answer is Oxytocin.

• Milk letdown means  ejection of a mor's milk from alveoli of breast into mammary ducts and to nipple.
• When nipple is sucked Prolactin acts on milk-making tissues.
• The Oxytocin hormone causes breast to push out or 'let down' milk.

Additional Information

Prolactin

• Prolactin is a hormone produced by  pituitary gland which sits at bottom of brain.
• Prolactin causes breasts to grow and develop and causes milk to be made after a baby is born.

Oestrogen

• Oestrogen is primary female sex hormone.
• It is responsible for development and regulation of female reproductive system and secondary sex characteristics.

Progesterone

• Progesterone prepares endometrium for potential of pregnancy after ovulation.
• It triggers lining to thicken to accept a fertilized egg.

The correct answer is Follicle-stimulating hormone.

• Follicle-stimulating hormone (FSH) is correct answer.
• The puberty age of females is 13 to 15 years. 

Key Points

• At this stage of puberty, FSH hormone begins producing and induces development of ovaries which result in hormone estrogen.
• This hormone is also responsible for development of secondary sexual character; induces voice change, body hair, breast, feminine shape, and external genitalia.
• Prolactin is hormone that stimulates milk production and is released from anterior lobe of pituitary and oxytocin is responsible for ejection of milk and is released from posterior lobe of pituitary gland.

The correct answer is Testosterone.

• Testosterone causes changes in appearance seen in boys at time of puberty.
• Puberty is process of physical changes through which a child's body matures into an adult body capable of sexual reproduction.

Key Points

• For guys, se hormones travel through blood and give testes signal to begin production of testosterone and sperm.
• Testosterone is hormone that causes most of changes in a guy's body during puberty.
• Sex hormones are chemical substances produced by sex organs.
  • For example, Testosterone is male sex hormone produced by testis, and estrogen is female sex hormone produced by ovary. These hormones affect sexual features of an organism.

Additional Information

• Functions of sex hormones:
  • Testosterone: This hormone brings about secondary sex characters in boys such as growth of a beard, voice becoming hoarse, development of reproductive organs, etc.
  • Oestrogen: This hormone is responsible for development of secondary sexual characters in females such as enlargement of breasts, development of female reproductive organs, etc.

Important Points