Arrange the following in the decreasing order (most important first) of their importance, for the welfare of human society. Give reasons for your answer. Biogas,citric acid,Penicillin and curd.

Why is aerobic degradation more important than anaerobic degradation for the treatment of large volumes of waste water in organic matter. Discuss.

(a) Discuss about the major programs that the Ministry of Environment and Forests, Government of India, has initiated for saving major Indian rivers from pollution.

Which type of food would contain lactic acid bacteria? Discuss their useful application.

Explain biological control of pests and plant pathogens with examples.

Rahul was not getting a good yield from the fields but his neighbours used to apply fertilizers to get higher yields of different crops.He consulted an agricultural scientist, living in the neighbouring town, to suggest some cheap and eco-friendly method to boost crop production.The scientist suggested him to use biofertilizers.
(i) What are bio fertilisers?
(ii) Name two examples of bio fertilisers.
(iii) Why did scientist advise Rahul to use bio fertilisers?

Protein is an important constituent of our food and its deficiency leads to many health problems.A large population of developing countries can not afford pulses.Ramesh learnt that many so he thought of culturing these microorganisms to provide a cheap source of proteins.
Read the above passage and answer the following questions:
(i) What are single cell protein (SCP)?
(ii) Name two microorganisms which provide SCP.
(iii) Why did Ramesh want to culture microorganisms?

Draw labelled sketch of a typical biogas plant.

Name the category of microbes occurring naturally in sewage and making it less polluted during the treatment.
(b) Explain the different steps involved in the secondary treatment of sewage.

A student as a part of his project visited a software company and was surprised to see a sewage treatment plant set up there. He wonders at the role of microbes in one of its steps and specifies it in his project.
(a)How would he ave described the role of microbes in sewage treat ent plants?
(b) What would he say was the intention of such a set up?
(c)What value would he have imbibed from there