The first action spectrum based on photosynthesis was given by ______AJan IngenhouszBJoseph MathewCCornelius Van NeilDT. W. EngelmannAnswer: D. T. W. Engelmann Read Explanation: T. W. Engelmann discovered the first action spectrum based on photosynthesis. He split light into its spectral components VIBGYOR by using a prism. A green alga i.e. Cladophora was used to detect the sites of O2 evolution. Read more in App