2. what is the name of a reference tool that is produced by chemical manufacturers that provides information on the chemical identify of the hazardous material, its known acute and chronic effects, and exposure limits, among other things?

Explain how the number of similarities between the embryos from early stage to late stage is used as evidence of a common ancestry

18. which statement about cancer is 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.