Human activities, particularly the combustion of are altering the climate by increasing co2 in the atmosphere.
a) fossil fuels b) hydrogen fuel c) nuclear fuels d) alternative fuels

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