The correct option is 1 only
Explanation
Pollutants are broadly classified into biodegradable and non-biodegradable substances based on their ability to be broken down by biological processes. Non-biodegradable substances cannot be decomposed by micro-organisms like bacteria and fungi, leading to their accumulation in the environment.
Statement-wise Analysis
- Statement 1 is Correct: Non-biodegradable substances persist in the environment for very long periods because natural biological agents cannot degrade them. Some of these substances may be chemically inert (unreactive) yet remain persistent, accumulating in the ecosystem without breaking down. Examples include certain types of plastics, glass, and heavy metals.
- Statement 2 is Incorrect: While non-biodegradable substances are generally pollutants, the statement that they "actively harm every member" is an exaggeration. Some substances may be inert and physically present without causing immediate active harm to specific organisms (e.g., a glass bottle buried in soil may not actively harm a nearby tree). However, they pose long-term risks through accumulation.
- Statement 3 is Incorrect: The defining characteristic of non-biodegradable substances is that they are not easily metabolized or broken down by biological organisms. If they were rapidly metabolized by all ecosystem members, they would be classified as biodegradable. Instead, they often undergo bioaccumulation and biomagnification because organisms cannot metabolize or excrete them efficiently.
Key Takeaway: Non-biodegradable pollutants are characterized by their persistence in the environment and inability to be decomposed by biological processes, leading to phenomena like biomagnification.