Why is there a great concern about the 'microbeads' that are released into environment?

1. A

   They are considered harmful to marine ecosystems.

   (a) Harmful to marine ecosystems. Microbeads are plastic micro-particles in cosmetics and personal care; they pass sewage works, load the sea, and are ingested by plankton and fish. That marine-ecosystem harm is the official key.

2. B

   They are considered to cause skin cancer in children.

   (b) Skin cancer in children. That is not the scientific case against microbeads, so this is not the key.

3. C

   They are small enough to be absorbed by crop plants in irrigated fields.

   (c) Absorbed by crop plants in irrigated fields. The policy concern is aquatic microplastics, not crop uptake as the headline risk, so this is not the key.

4. D

   They are often found to be used as food adulterants.

   (d) Food adulterants. Microbeads are not used as food adulterants; this is not the key.

Summary. Official key is (a). Microbeads are engineered microplastics washed from scrubs and toothpastes into rivers and oceans. Several countries, including India in later plastic rules, moved to restrict them because of marine food-web contamination. Honour the stored letter (a).