Need Now Which statement is true concerning all organisms? A. All organisms respond to their environment. B. All organisms are made of many cells. C. All organisms obtain energy from other organisms. D. All of these statements are true.

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.