20. Hmmm. Obviously it is a fact.The issue is it a True fact, or a false fact. I judge it False. RDA carries many more than 4 reference values, see this chart http://www.time-to-run.com/nutrition/wp-content/uploads/1RDA1.gif
29. I cant beleive you asked that. Which would grandma feed you when you are sick in bed?
last one: I assume you are 17 yr old female. If your maximum heart rate is 204, you are likely undergoing atrial fibrillation, or near it, and you need to see a cardiologist immediately.
see the charts here. http://www.heart.com/heart-rate-chart.html
I'm 16..don't you get your maximum heart rate by subtracting your age from 220? ...
Target heart rate zone= 104
That formula is widely discredited. I don't know what to tell you.
While the most common (and easy to remember and calculate), this particular formula is not considered by reputable health and fitness professionals to be a good predictor of HRmax. Despite the widespread publication of this formula, research spanning two decades reveals its large inherent error (Sxy = 7–11 b/min). Consequently, the estimation calculated by HRmax = 220 − age has neither the accuracy nor the scientific merit for use in exercise physiology and related fields. http://en.wikipedia.org/wiki/Heart_rate
If you have a heart rate at 16, female, and you register 204, I would see a cardiologist for a check up. In women, artial fibrillation is a very common condition that leads to ...death...
Read about it.
So if 104 is what your book says, give it back to them as the "right" answer.
I am not sure what you are looking for with "target heart rate." A normal heart rate for a 17yo and adults is 60-100. Above is termed tachycardia. Below is bradycardia. Generally, your base heart rate is lower the more fit and athletic you are. So, if I were looking for a "target" I would shoot for the normal range. Hope this helps.