Correct Option
The correct option is 2 and 3 only.
Explanation
Living organisms are classified based on their mode of nutrition into autotrophs and heterotrophs. This classification depends on the source of carbon and energy used by the organism to sustain life processes.
Statement-wise Analysis
- Statement 1 is Incorrect. Autotrophs (such as green plants and certain bacteria) do not utilize complex organic substances as raw materials. Instead, they utilize simple inorganic substances like carbon dioxide and water from the environment to synthesize complex organic substances (carbohydrates) in the presence of sunlight and chlorophyll.
- Statement 2 is Correct. Heterotrophs utilize complex organic substances derived from other organisms. These complex substances cannot be used directly by the body for maintenance and growth; they must be broken down into simpler, soluble forms. This breakdown is achieved through the action of bio-catalysts known as enzymes.
- Statement 3 is Correct. Heterotrophs lack the ability to synthesize their own food from inorganic raw materials. Consequently, they depend directly (herbivores) or indirectly (carnivores) on autotrophs for their energy and survival requirements.
Key Takeaway
Autotrophs synthesize food using simple inorganic raw materials (CO2, H2O), whereas heterotrophs consume complex organic matter and rely on enzymes to digest it into simpler forms.