Which of the following organisms can prepare their own food by Photosynthesis?

Concept: Organisms are classified by their mode of nutrition. Autotrophs (producers) can manufacture their own food from simple inorganic substances; chlorophyll-bearing organisms do this through photosynthesis, using sunlight energy to convert carbon dioxide and water into glucose. Heterotrophs cannot make their own food and must obtain organic nutrients from other organisms (as saprophytes, parasites, or symbionts), while viruses are acellular particles with no independent metabolism of their own.

Application: Checking each organism listed in the question for the presence of chlorophyll and a working photosynthetic apparatus identifies which one is a true autotroph.

• Algae contain chlorophyll a (and, in many groups, chlorophyll b or other accessory pigments) in chloroplasts, allowing true photosynthesis — they are autotrophic producers.

• Fungi have no chlorophyll; they are heterotrophic and absorb ready-made organic nutrients from dead matter (saprophytic), living host organisms (parasitic), or partner organisms (symbiotic).

• Rhizobium is a nitrogen-fixing bacterium living symbiotically in the root nodules of leguminous plants; it fixes atmospheric nitrogen for the host but has no chlorophyll and cannot photosynthesise.

• Virus is an acellular obligate intracellular parasite with no metabolic machinery of its own, so it cannot carry out photosynthesis or any independent life process.

Result: Only Algae possess chlorophyll and functional chloroplasts, so they are the organism among those listed that can prepare their own food by photosynthesis — matching the official CTET 2019 Paper II answer key.