A student wants to compare the energy released per gram of glucose by aerobic and anaerobic respiration. The student measures the total energy released by two cell cultures.
The aerobic culture releases more energy, but the mass of glucose used by each culture is unknown.
Why is the comparison incomplete?
the cultures may have broken down different masses of glucose
the aerobic culture must have produced glucose while releasing energy
the anaerobic culture cannot have broken down any of the glucose
the cultures must have released the same energy per gram of glucose
42 exam-style questions on Edexcel GCSE Biology 8.3 Respiration, covering 8.3.1 Aerobic and anaerobic respiration. Each one has a worked solution and a mark scheme showing where the marks go.