Multiple choice Which of the following pairs is incorrectly matched? Emerson and Arnold - Existence of light and dark reactions in photosynthesis Engelmann - Chloroplasts as the site of photosynthesis Hatch and Slack - C3 pathway for CO2 fixation Ruben and Kamen - Oxygen comes from water in photosynthesis Peter Mitchell - Chemiosmotic hypothesis of ATP synthesis in light reaction Reveal answer Fill a bubble to check yourself C Correct answer Explanation In 1966, Hatch and Slack reported the C4 pathway for CO2 fixation in certain tropical plants. In 1954, Melvin Calvin traced the path of carbon in photosynthesis and gave the C3 cycle (now known as Calvin cycle).