Which four nitrogenous bases are found in DNA? 1 guanine, cytosine, adenine, thymine
2 guanine, uracil, adenine, cytosine
3 both a and b
4 none of the above

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

What evidence did mendel find that supported his law of independent assortment? a. some traits are controlled by several different genes. b. a trait can be passed on from a parent to an offspring. c. most traits have a dominant form and a recessive form. d. different traits are passed on independently of each other.

Which short-term environmental changes would a very small asteroid or comet impact on earth most likely cause? check all that apply. flooding extinction craters on surface changes in weather patterns death of organisms and populations