The possession of chloroplast in Euglena virids enables it to

Step 1: Analyze the question The question asks what the chloroplast allows Euglena viridis to do. So we need the main function of the chloroplast.

Step 2: Explain the concept Euglena is a unicellular, protist-like organism that has features of both plants and animals.

• Chloroplasts contain chlorophyll, the green pigment that traps light energy for photosynthesis (making food from carbon dioxide and water).
• Euglena also has an eyespot (stigma), which detects light. That is a separate structure from the chloroplast.
• It stores food as paramylon, not true starch.
• It reproduces by binary fission, which does not depend on chloroplasts.

Step 3: Evaluate the options

• A. Store starch: Incorrect. Euglena stores food as paramylon, and storage is not the primary role of the chloroplast.
• B. Carry out photosynthesis: Correct. This is the direct function of chloroplasts, and it makes Euglena autotrophic (holophytic) when light is available.
• C. Reproduce: Incorrect. Reproduction is by binary fission, which is unrelated to chloroplasts.
• D. Respond to light: Incorrect. This is the job of the eyespot and the photoreceptor, not the chloroplast.

Step 4: Answer The possession of chloroplasts enables Euglena viridis to carry out photosynthesis.

Exam tip: Match each organelle to its function. Chloroplast = photosynthesis, eyespot = light detection, flagellum = movement, contractile vacuole = osmoregulation. Questions like this often test whether you can tell these apart.