Which of the following are not biodegradable?
A. Plastic mugs
B. Eggshell
C. Leather belt
D. Both A and C

Answer Verified Verified
Hint: Biodegradable wastes are the materials or the substance which can be easily broken down or decomposed into simpler units by the natural agents such as microbes, sunlight, etc. whereas nonbiodegradable are the substances which cannot be broken down or are nondegradable easily.

Complete answer: Plastic is composed of artificial polymer, as they are synthesized using chemicals such as polypropylene polystyrene, polyethylene, etc. Which makes them non-degradable.
Eggshell is composed of calcium carbonate ($CaCO_3$), Eggshell consists of 95 % $CaCO_3$ is a product of nature i.e. a product obtained naturally it can be degradable from which we can infer that they are biodegradable.
Leather belts are manufactured using solid cowhide, pigskin or any other cattle hide. Several tanning processes transform hides and skins into the leather by using chromium tannin etc..
As the main constituent of the leather belt is part of a living organism it is biodegradable.

Additional information: The biodegradable waste is eco friendly, the degraded waste can be utilized as fertilizers, manure, compost. They are non-toxic to the environment.
On the other hand non-biodegradable waste is non-eco-friendly being not degradable they are a major threat to the environment.

So the correct answer is option A. Plastic mugs

Note: Leather belt may seem non-biodegradable as they are manmade products. But they are made from the animal or living organism part i.e. Cattle hide which makes them biodegradable. The chemicals used in the tanning of belts make this biodegradable process slow.