Apopulation of crocodiles is in hardy weinberg equilibrium which condition must be true

no new mutations have occurred

genetic drift is taking place

natural selection is causing changes in allele frequencies

new individuals are migrating into the population

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.