Two samples are spotted onto a thin-layer chromatography (TLC) plate, and the plate is developed and visualized. The result is that Sample A separates into three visible spots and Sample B only gives one visible spot. Based on the given information, select the statement that is NOT necessarily true.

A. Sample A contains at least three compounds
B. Sample B contains at least one compound
C. Sample A contains exactly three compounds
D. Sample A contains more than one compound

Which of the following characteristics are true of enzymes? check all that apply. a.)the structure of an enzyme can change if conditions change. b.)a single enzyme can normally catalyze a wide variety of reactions under many conditions. c.)enzymes are found only in nonliving systems. d.)enzymes allow living things to regulate body conditions through feedback mechanisms. e.)enzymes bind to specific substrates in specific ways. f.)enzymes increase the rate of reaction. g.)when shown in energy-reaction diagrams, enzymes represent the higher activation energy.