Correct Option
The correct option is 2 and 3 only.
Explanation
In biological systems, growth is defined as an irreversible, permanent increase in the size of an organ, its parts, or an individual cell. It is one of the most fundamental characteristics of living beings and is intrinsically linked to metabolic activities.
Statement-wise Analysis
- Statement 1 is Incorrect: Simple imbibition refers to the absorption of water by solid particles (e.g., a piece of wood swelling when wet). While this results in an increase in size, it is a physical and reversible process. It does not involve the synthesis of protoplasm or permanent structural development, and thus does not qualify as biological growth.
- Statement 2 is Correct: The expansion of a leaf involves cell division and cell enlargement, resulting in a permanent increase in surface area and volume. This is a definitive example of growth in plants.
- Statement 3 is Correct: Growth is strictly accompanied by metabolic processes. It occurs when anabolic (synthetic) processes exceed catabolic (destructive) processes, requiring the expenditure of energy to synthesize new protoplasm and structural materials.
- Statement 4 is Incorrect: A defining characteristic of true growth is that it is irreversible. Once an organism or organ has grown (increased in dry weight or size), it cannot naturally revert to its original dimensions, unlike reversible changes caused by turgor pressure or water absorption.
Key Takeaway
Key Takeaway: Biological growth is characterized by a permanent and irreversible increase in size, mass, or volume, driven by metabolic processes where synthesis exceeds breakdown.