Sorting Materials into Groups

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

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

Which of the following groups of organisms convert organic materials to inorganic forms ?

Cement, the important building material is a mixture of oxides of several elements. Besides calcium, iron and sulphur, oxides of elements of which of the group (s) are present in the mixture ?