How are complementary strands of dna held together?

What is the process of pulling apart an n2 molecule nevermind i got it

Which of the following explains why a tree is often used as a model to represent the principle of common descent

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