Correct Answer: An organelle called Eyespot allows some protists to detect light It allows the cells to sense light direction and intensity and respond to it by swimming either towards the light (positive phototaxis) or away from the light (negative phototaxis) Eyespot is a photoreceptive organelle found in the flagellate or (motile) cells of green algae and other unicellular photosynthetic organisms such as euglenids Eyespot-mediated light perception helps the cells in finding an environment with optimal light conditions for photosynthesis Eyespots are the simplest and most common "eyes" found in nature, composed of photoreceptors and areas of bright orange-red pigment granules
