In the context of solving pollution problems, what is/are the advantage/advantages of bioremediation technique ? 1. It is a technique for cleaning up pollution by enhancing the same biodegradation process that occurs in nature. 2. Any contaminant with heavy metals such as cadmium and lead can be readily and completely treated by bioremediation using microorganisms. 3. Genetic engineering can be used to create microorganisins specifically designed for bioremediation. Select the correct answer using the code given below:

Bioremediation uses living organisms, mostly bacteria and fungi, to break down or detoxify pollutants. Its core idea is to speed up the biodegradation that already happens in nature, so statement 1 is correct. Statement 3 is also correct: genetically engineered microbes can be designed for specific pollutants, and this is an active area of biotechnology.

Statement 2 is wrong. Microbes can degrade organic contaminants such as hydrocarbons, but heavy metals like cadmium and lead are elements and cannot be destroyed or fully broken down. Microbes can at most immobilise, precipitate or change the oxidation state of a metal, which reduces its toxicity or mobility without removing it. So the claim that such contamination is 'readily and completely' treated is incorrect.

Hence the answer is C, 1 and 3 only.

Mains connection: bioremediation features in discussions of contaminated sites and in environmental management under the Environment (Protection) Act, 1986, where the limits of biological treatment for metals matter.

Trap: students tend to accept the broad claim that bioremediation works on any contaminant. The words 'any' and 'completely' in statement 2 are the giveaway.