Observe the diagram of the catalytic converter and answer the questions which follow.

(a) Name any two metals used as catalyst in the catalytic converter.

(b) Name the gases released after passing the exhaust hydrocarbons through the catalytic converter.

(c) Which other poisonous gas is missing in the exhaust pollutant of an automobile in the above diagram?

With reference to the above schematic diagram of Spermatogenesis (a) and Oogenesis (b), answer the following questions:

a) About 300 million spermatozoa may be present in a human male ejaculation at one time. Calculate how many spermatocytes will be involved to produce this number of spermatozoa.

b) How many spermatids will be formed?

c) How many chromatids are found during Oogenesis in Primary oocyte and First polar body in a human female?

Large quantities of sewage is generated every day in cities and towns, which is treated in Sewage Treatment Plants (STPs) to make it less polluting. Given below is the flow diagram of one of the stages of STP. Observe the given flow diagram and answer the questions accordingly.

(a) Why primary effluent is passed into large aeration tanks?

(b) What is the scientific term used for the sediment formed? Mention its significance.

(c) Explain the final step resulting in the formation of biogas in the large tank before the treated effluent is released into water bodies.

Certain phenotypes in human population are spread over a gradient and reflect the contribution of more than two genes. What is the term used for the types of inheritance? Describe it with the help of an example in human population.

OR

Summarize the process by which the sequence of DNA bases in Human Genome Project was determined using the method developed by Frederick Sanger. Name a free living non-pathogenic nematode who’s DNA has been sequenced.

(a) What is mutation breeding? Give an example of a crop and disease to which resistance was induced by mutation.

(b) Differentiate between pisciculture and aquaculture.

OR

a) If a patient is advised anti-retroviral drug, which infection is he suffering from? Name the causative organism.

b) How do vaccines prevent subsequent microbial infections?

c) How a cancerous cell differs from the normal cell?

d) Many microbial pathogens enter the gut of humans along with food. Name the physiological barrier that protects the body from such pathogens.