Which one the following is statements is true?

a) exposure to antibiotics causes individual bacteria to mutate and become resistant

b) crossing over and random fertilization decrease variation

c) natural selection works on variation already present in a population

d) organisms evolve structures that they need

e) none of the above

Previous pagenext pagepage 3 of 10question 3 (1 point)which of the following consist of cells that do not have a nucleus? of the above

What best describes the structure of the declaration of independence?

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