What is the answer it is hard

28. how many linkage groups will be formed by homogametic organism with 28 chromosomes?

Blank is a rock with a find dark texture that makes up the oceanic crust

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.