Amethod of separation that employs a system with two phases of matter, a mobile phase and a stationary phase, is called

Which of the following statements is true? a. elements in the last period are radioactive. b. atomic weight is the same as atomic mass. c. elements in the same group have the same number of electron shells. d. atomic number equals the number of neutrons in the nucleus of an atom.

This chart lists four kinds of polymers and their sources. what can be known about all four polymers, despite their differences? they come from living things. they share ionic carbon bonds. they are at least 100 monomers long. they are made of repeating subunits.

Which polymers are most closely related? a. protein and nucleic acids b. cellulose and starch c. nucleic acids and starch d. nucleic acids and cellulose