Question

question 5
water - soluble vitamins:
are easily excreted in the urine.
are needed in periodic doses
often result in toxicities among infants and children.
are stored in the liver

question 6
vitamin a plays an important role in:
night vision
blood clotting
fluid and electrolyte balance
promoting keratinization.
calcium regulation.

Explanation:

Question 5

• For water - soluble vitamins:
• Option "are easily excreted in the urine": Water - soluble vitamins (like B - complex, vitamin C) dissolve in water. Since the body can't store large amounts of them, excess amounts are excreted in urine.
• Option "are needed in periodic doses": Fat - soluble vitamins are stored in the body and can be used over time, so water - soluble vitamins need regular intake, but the statement "easily excreted in urine" is a more defining characteristic of water - soluble vitamins.
• Option "often result in toxicities among infants and children": Toxicities from vitamins are more common with fat - soluble vitamins (as they are stored), not water - soluble.
• Option "are stored in the liver": Fat - soluble vitamins (A, D, E, K) are stored in the liver and adipose tissue, not water - soluble. So the correct option is the one about being excreted in urine.

• Vitamin A:
• Option "night vision": Vitamin A is a component of rhodopsin, a pigment in the retina that is essential for low - light (night) vision.
• Option "blood clotting": Vitamin K is involved in blood clotting.
• Option "fluid and electrolyte balance": Minerals like sodium, potassium are involved in fluid and electrolyte balance.
• Option "promoting keratinization": Vitamin A deficiency can lead to keratinization (hardening of epithelial cells), but its main role is in vision.
• Option "calcium regulation": Vitamin D is involved in calcium regulation. So the correct option is related to night vision.

Answer:

A. are easily excreted in the urine.

Question 6