What is the active form of vitamin A?

What is the active form of vitamin D?

What condition is characterized by severe dry eyes and is associated with vitamin A deficiency?

The inactive form of vitamin A found in orange vegetables (e.g., carrots, sweet potatoes) is:

Which of the following is major carotenoid in carrots?

Which type of ultraviolet radiation is needed to produce vitamin D in the skin?

Which type of vitamin D is made in the skin and works better at raising vitamin D levels in the blood?

What is the primary function of vitamin D in the body?

What is a known effect of vitamin E in the body?

Which of the following roles does vitamin K play in the body?

What condition is caused by the deficiency of vitamin B1?

Which vitamin deficiency leads to the condition known as pellagra?

What are the three main symptoms of pellagra?

Which vitamin is essential for red blood cell formation and brain function?

The only water-soluble vitamin that can be stored in the body is:

What is a potential side effect of taking an overdose of vitamin C?