Which statement is true of atoms? Group of answer choices Electrons determine the atom's size. Protons repel electrons. Most of an atom's volume is filled with matter. Protons attract other protons.

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.