In the following groups of materials, which group/groups contain only non-biodegradable materials ?
(i) wood, paper, leather
(ii) polythene, detergent, PVC
(iii) plastic, detergent, grass
(iv) plastic, Bakelite, DDT
Polythene, detergent, PVC, Plastic, Bakelite and DDT are non-biodegradable materials i.e. they cannot be degraded.