The periodic table includes all of the known elements in the world. How are elements arranged on the periodic table?
a. by the element's name
b. by their atomic mass
c. by the number of neutrons found in the element
d. by their atomic number

Consider a culture medium on which only gram-positive organisms such as staphylococcus aureus colonies can grow due to an elevated nacl level. a yellow halo surrounds the growth, indicating the bacterium fermented a sugar in the medium, decreasing the ph as a result and changing the color of a ph indicator chemical. this type of medium would be referred to as a differential and enrichment culture.