Water pollution does NOT contribute to which of the following problems? — Human illnesses
— Global warming
— Mutated fish
— Weak crops

The distant ancestors of tigers may have had bodies without stripes. use the theory of natural selection to explain how tigers may have evolved to have stripes.

The dense layer of connective tissue that surrounds an entire skeletal muscle is the

Which of the following must be true for a fossil organism to be useful as an index fossil? a. the fossil organism must be widespread geographically. b. the fossil organism must be abundant. c. the fossil organism must be limited to a short span of geologic time. d. all of the above.