Why are enzymes necessary? a) to deter the rate of decomposition b)to act as a catalyst in chemical reactions c)to conserve the stored energy of a cell

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.