(a) Ozone is a colourless gas and chemically is very active; it reacts readily with a many other substances. Ozone gas shield the Earth surface from the harmful UV-radiations from the sun protecting living things below.

(b) The living things in an ecosystem are called biotic components in the ecosystem are the living things. Living things include plants, animals, bacteria, fungi. In an ecosystem. Abiotic components are non-living things. These includes sunlight, temperature atmospheric gases water and soil. Abiotic and biotic components interact each other in an ecosystem.

(c) Plastic are non-biodegradable substance. It cannot be degraded by decomposers. It remains in the environment for longer time and would have hazardous impact if it persists in the environment for a long time.