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 microorganisms specifically designed for bioremediation. Select the correct answer using the code given below:

1. Correct. Bioremediation uses or enhances natural biodegradation by microorganisms/plants to clean polluted soil, water or air. This is the basic principle of the technique.

2. Incorrect. Heavy metals like cadmium and lead are elements; they cannot be biodegraded or completely removed by microorganisms in the same way as organic pollutants. Bioremediation may immobilize or transform them, but not readily and completely treat them.

3. Correct. Genetic engineering can develop microorganisms with improved pollutant-degrading ability for specific bioremediation tasks.

Therefore, statements 1 and 3 only are correct.