Which of the following plants uses CAM (Crassulacean Acid Metabolism) photosynthesis?

• A. Zea mays (corn)
• B. Triticum aestivum (wheat)
• C. Opuntia (prickly pear cactus)
• D. Phaseolus vulgaris (common bean)

Answer: (C)

Verified step by step guidance

1. Understand what CAM (Crassulacean Acid Metabolism) photosynthesis is: it is a specialized form of photosynthesis adapted to arid conditions, where plants open their stomata at night to minimize water loss and fix CO2 into organic acids.
2. Recall that CAM photosynthesis is common in succulent plants, especially those adapted to dry environments, such as cacti and some orchids.
3. Review the list of plants given: Zea mays (corn), Triticum aestivum (wheat), Opuntia (prickly pear cactus), and Phaseolus vulgaris (common bean).
4. Identify which plants are typically found in dry environments and have succulent characteristics; Opuntia, a cactus, fits this description and is known to use CAM photosynthesis.
5. Conclude that among the options, Opuntia (prickly pear cactus) uses CAM photosynthesis, while the others use C3 or C4 pathways.