Question

pls say me 3,4,5,6 answer and if possible 7th too plssspls 2morrow is my exam pls

Answer 1

3. The solid waste material which can be degraded by micro-organisms are called biodegradable waste. e.g. vegitable waste, egg shells etc.
The solid waste which cannot be degraded by micro-organisms are called non-biodegradable waste. e.g. glass bottles scrabs metal etc.

Answer 2

biodegradable are those materials which can degrade themselves in short period of time naturally and not cause harm to our environment. for eg:- vegetable peels, kitchen waste etc.
non biodegradable are those which cannot degrade and cause harm to our environment. for eg:- plastic, polythene etc.

sewage treatment means removing all the impurities from the sewage water so that it can be used in homes.

there can be many substances which can be a cause of choking of drainage, a few are mentioned below :-
chemicals
fertilizers
pesticides
plastic
polythene
oil and fat
medicines etc.

biodegradable - fruit peels, cotton, paper, wood
non biodegradable - DDT, polythenes, plastic, tin can, tea leaf glass