The half-life of carbon-14 is 5,600 years. a fossil that has one-eighth the normal proportion of carbon-14 to carbon-12 is probably years old.

You and a group of friends are spending your vacation hiking through the mountains. it is cold in the mountains. you will be expending a lot of energy while hiking and you will need plenty of energy to keep you warm. you should pack foods high in to provide the most energy or kilocalories per gram of food. a) carbohydrates b) lipids (fats) c) proteins d) sugars