PDF chapter test TRY NOW

1. Excessive exposure of humans to U V-rays results in

(i) damage to immune system
(ii) damage to lungs
(iii) skin cancer
(iv) peptic ulcers
 
2. In the following groups of materials, which group (s) contains only non-biodegradable items?

(i) Wood, paper, leather
(ii) Polythene, detergent, PVC
(iii) Plastic, detergent, grass
(iv) Plastic, bakelite, DDT