Final answer:
Scenedesmus, Volvox, and Elodea all contain chloroplasts, as they are either chlorophyte green algae or aquatic plants. Protococcus is not well-defined but may refer to various forms of green algae which would also have chloroplasts.
Step-by-step explanation:
In biology, particularly in the study of green algae, we find that chloroplasts, which are the organelles responsible for photosynthesis, are present in several types of algae, including chlorophytes and charophytes. Among the four options given - Scenedesmus, Volvox, Elodea, and Protococcus - Scenedesmus, Volvox, and Elodea all contain chloroplasts.
Scenedesmus and Volvox are both chlorophyte green algae, which harbor chloroplasts for photosynthesis. Elodea is a common aquatic plant that also contains chloroplasts. Regarding Protococcus, it should be noted that it is not well-defined in current scientific literature, and may refer to an outdated term for various forms of green algae, many of which would also have chloroplasts. However, to accurately identify which organisms have chloroplasts, one can also consider whether the organism is a known green algal member or a plant, both of which would indeed contain chloroplasts.