In plants, tubes within the stems and leaves transport water throughout the plant. in a dog, which system parts would be similar? a. arteries and veins b. small and large intestine c. urethra and bladder d. ligaments and tendons

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.