Which of these is an example of science?

avoid black cats before important events
find out how temperature affects air in a balloon
find out the position of stars to predict future events
use bumps on a human head to determine personality traits

B. The first one is superstition, the third is astronomy, and the fourth is fake news.

image result for how many calories of energy will 20 grams of carbohydrates provide in one gram provides 4 calories

consuming the right balance of protein, carbohydrates and fat can you maintain a healthy weight and optimize your energy levels. protein and carbohydrates both contain 4 calories per gram, while fat provides 9 calories per gram.

"a.) well–developed vascular system."