The main source of information used by astronomers to learn about objects in space is A. electromagnetic waves B. Comets C. Meteorites D. Constellation

How does the molecular clock work? a. it analyzes the brain functionality of two different species.b. it examines and compares the physical characteristics of two different species.c. it illustrates relationships between two different species.d. it compares the number of mutations that exist in the dna of two different species.

Which is not a characteristic of bacteria? a. they are unicellular. b. they are prokaryotic. c. they are the smallest form of life on earth. d. they are multicellular.

What substance is the most acidic. lemon juice. tomato juice. sodium hydroxide. water