cardiotonic is a drug or substance having a tonic effect on heart.
Answer: Ambulatory monitoring of the electrocardiogram in 100 healthy 14 to 16 year old boys showed heart rates ranging from 45 to 200 beats/minute during the day and from 23 to 95 beats/minute during sleep.
<span>Fat-soluble vitamins: A, D, E, and K — are stored in the body for long periods of time, and pose a greater risk for toxicity than water-soluble vitamins. Fat-soluble vitamins are only needed in small amounts.
So your answer would be D</span>. Vitamin D
