Thugh they are photosynthetic in the presence of sunlight when deprived of sunlight they behave like heterotrophs predating on other smaller organisms. They are:

Options

A. Slime moulds
B. Protozoans
C. Chrysophytes
D. Euglenoids

Answer

**Step-by-Step Solution:**

1. **Understanding the Characteristics**: The question describes an organism that is photosynthetic in the presence of sunlight but behaves like a heterotroph when sunlight is absent. This means it can produce its own food through photosynthesis but also has the ability to consume other organisms for nutrition.

2. **Identifying the Organisms**: The options given are slime molds, protozoans, chrysophytes, and euglenoids. We need to analyze each option to determine which one fits the description.

3. **Analyzing Slime Molds**: Slime molds are a type of protist that are generally saprophytic, meaning they feed on decaying organic matter. They do not perform photosynthesis, so they can be eliminated as a possible answer.

4. **Analyzing Protozoans**: Protozoans are primarily heterotrophic and do not perform photosynthesis. They obtain nutrients by consuming other organisms. Therefore, they do not fit the description either.

5. **Analyzing Chrysophytes**: Chrysophytes include diatoms and golden algae, which are mainly photosynthetic. However, they do not exhibit the heterotrophic behavior described in the question.

6. **Analyzing Euglenoids**: Euglenoids, such as Euglena, are unique because they can perform photosynthesis in the presence of sunlight due to their chloroplasts. However, when sunlight is not available, they can switch to a heterotrophic mode of nutrition by consuming smaller organisms. This dual behavior makes them the correct answer.

7. **Conclusion**: Based on the analysis, the organism that fits the description of being photosynthetic in sunlight and heterotrophic in the absence of sunlight is **Euglena**.

**Final Answer**: Euglena

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