Echinacea is an herbal supplement that is often used an over-the-counter cold remedy. A team of scientists decided to investigate its effectiveness. They hypothesized that echinacea reduces the effect of the common cold on the body because it boosts the ability of the immune system to fight off the virus. The images below report the experimental design and the results. Based on this information, choose the best conclusion for the study from the provided options.

Keeping in mind the Daphne Major finches from the previous question, what type of variation in finches is passed to the offspring?

What should you do after a primary survey in which you did NOT determine that a potentially catastrophic injury was present?

Which of the following collisions would an individual be susceptible to most severe injury.

Which of the following is the best description of the law of independent assortment?

Which of the following is an objective finding?

How might an evolutionary biologist explain why a species of salamander becomes blind after colonizing a cave?

Which of the following is the dependent variable? Choose the best answer. 

How did the population of birds develop insulating feathers during an ice age rather than, say, becoming featherless and naked?

Cotton-topped tamarins are small primates with tufts of long white hair on their heads. While studying these creatures, you notice that males with longer hair get more opportunities to mate and father more offspring. To test the hypothesis that having longer hair is adaptive in these males, you should ________. (Choose the best answer)