Identify'A' , 'B', 'C' and 'D' in the given table

Crop	Variety	Resistance to disease
A	Himgiri	Leaf rust
Cauliflower	Pusa Shubhra	B
Brassica	Pusa Swarnim	C
Cowpea	D	Bacterial blight

How has RNAi technique helped to prevent the infestation of roots in tobacco plants by a nematode Meloidegyne incognita?

Give an example of an autosomal recessive trait in humans. Explain its pattern of inheritance with the help of a cross. 

In in a food-chain, a trophic level represents a functional level, not a species. Explain.

During a school trip to 'Rohtang pass' one of your classmate suddenly developed 'Altitude sickness'. But, she recovered after sometime.

(a) Mention one symptom to diagnose the sickness.
(b) What causes the sickness?
(c) How could she recover by herself after sometime?

What is a GMO? List any five possible advantages of a GMO is a farmer. 

Plant breeding technique has helped sugar industry in North India. Explain how.

Why is breast-feeding recommended during the initial period od an infant's growth? Give reasons. 

Suggest and describe a technique to obtain multiple copies of a gene of interest in vitro.