(a) State one difference between arteries and veins.
​(b) Name any two sexually transmitted diseases. What advice is given to prevent them?

(a)

Arteries	Veins
They carry oxygenated blood from the heart to the other parts of the body. The pulmonary artery is an exception as it carries deoxygenated blood from the heart to lungs.	They carry deoxygenated blood from the body to the heart. The pulmonary vein is an exception as it carries oxygenated blood from the heart to lungs.

(b) Syphilis and AIDS are two sexually transmitted diseases. Such diseases can be prevented by the use of condoms.

Condoms are made of thin rubber and are used to cover the penis and the vagina in males and females, respectively.