The correct option is 1 and 3 only.
Explanation
Producers, also known as autotrophs, are organisms that synthesize their own organic food from inorganic raw materials. They constitute the first trophic level in a food chain and are the primary source of energy for all other organisms in an ecosystem.
Statement-wise Analysis:
- Statement 1 is Correct: The majority of producers, specifically photoautotrophs, utilize the process of photosynthesis to capture solar energy and convert it into chemical energy stored in the bonds of carbohydrates (glucose). This energy drives the ecosystem.
- Statement 2 is Incorrect: Producers are not limited to green plants. In aquatic ecosystems, phytoplankton (microscopic algae) are the major producers. Additionally, certain bacteria and protists also function as producers. Therefore, the exclusivity implied by "only" makes this statement invalid.
- Statement 3 is Correct: Various types of bacteria act as producers. This includes cyanobacteria (blue-green algae), which are photosynthetic. Furthermore, chemosynthetic bacteria (chemoautotrophs) found in extreme environments like deep-sea hydrothermal vents produce food by oxidizing inorganic chemical substances (such as hydrogen sulfide) rather than using sunlight.
Key Takeaway:
Producers (autotrophs) include green plants, algae, and certain bacteria (both photosynthetic and chemosynthetic). They are defined by their ability to synthesize food, not solely by their classification as plants.