Answer any two of the parts (a), (b), (c) - Leaving Cert Biology - Question 14 - 2010

Part D, the vas deferens, functions to carry sperm from the testis to the urethra during ejaculation.

The principal male sex hormone is testosterone.

Two male secondary sexual characteristics include:

1. Deep voice/enlarged testes
2. Facial hair/chest hair

A human sperm cell consists of three main parts: head, midpiece, and tail. The head contains the nucleus with genetic material, while the midpiece is packed with mitochondria for energy. The tail enables motility.

The placenta is formed from the maternal tissues and fetal tissues, particularly from the chorion of the fetus and the decidua basalis of the mother.

Two functions of the placenta are:

1. To allow nutrients and oxygen to pass to the fetus while removing carbon dioxide and waste.
2. To produce hormones such as progesterone that help maintain pregnancy.

The process of birth involves three main stages:

1. Dilation of the cervix, where contractions help the cervix open to allow the baby to pass through.
2. Delivery of the baby, where the fetus is pushed out through the birth canal.
3. Delivery of the placenta, which occurs after the baby is born.

One biological benefit of breastfeeding is that it provides essential nutrients and antibodies to the baby, boosting their immune system.

Two methods of contraception include:

1. Condoms
2. Oral contraceptive pills