Carrots are the richest source of beta-carotene, which is important compound in its role a precursor to vitamin A production, also is known as a inner body cancer fighter in its own right
There is a strong link between regular carrot consumption and reduced cancer risks, recent experiment have shown in some cases that carrot can reverse the malignant changes in cells.
Vitamin A has a strong role as it helps skin, heart & liver function and healthy eyesight, this is not saying you will be able to see night but beta-carotene does help vision.
Also you can find vitamin E and fibre great for internal organs and important for the respiratory system.