Short Answer TypeIdentify'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 |
Why is breast-feeding recommended during the initial period od an infant's growth? Give reasons.
Give an example of an autosomal recessive trait in humans. Explain its pattern of inheritance with the help of a cross.
Louis Pasteur suggested that life propagated only from the pre-existing life forms. He conducted the swan-necked flask experiment and proved his point on the continuity of life.
His experiment was as follows:
• Two swan-necked flasks containing nutrient broth were used.
• The broth in both the flasks was boiled to kill any existing microbes and was made sterile.
• After sterilisation one of the flask necks was broken. The flasks were kept undisturbed for some time.
• After some time, the dust particles along with bacteria in the air entered the flask with the broken neck and got accumulated at the neck of the unbroken flask.
• The broth in the broken flask became cloudy, while the broth in the unbroken flask remained clear. Cloudiness of the broth indicated the presence of microbial life in the broken flask.
• Appearance of life, even after sterilisation, in the broken flask concluded that life in the flask arose only from pre-existing life; thus, and discarded the theory of spontaneous generation.
Suggest and describe a technique to obtain multiple copies of a gene of interest in vitro.
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?
How has RNAi technique helped to prevent the infestation of roots in tobacco plants by a nematode Meloidegyne incognita?
In in a food-chain, a trophic level represents a functional level, not a species. Explain.
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