What does it mean to say that two different species of organisms are closely related? a. they have the same preferences in diet. b. they have a common evolutionary ancestor. c. they live in the same habitat. d. they have the same parents.

Why do mutations in genes affect traits? o a. genes determine what type of mutagens an organism has. o b. genes produce proteins that cause traits. o c. genes affect how many chromosomes an organism has o d. genes code for carbohydrates that influence traits.

Which description provides the best objective summary of the article in the passage?

Which of these substances does not protect against invaders in the nonspecific immune response? a. saliva b. mucus c. tears d. urine