Which of the following groups contain only biodegradable items?
a. Grass, flowers and leather
b. Grass, wood and plastic
c. Fruit peels, cake and lime juice
d. Cake, wood and grass

The groups (a), (c) and (d) contains only biodegradable items.

(a) Grass, flowers and leather

(c) Fruit peels, cake and lime juice

(d) Cake, wood and grass

The group (b) has plastic in it which is a non-biodegradable item.