In in a food-chain, a trophic level represents a functional level, not a species. Explain.
In a food chain one trophic level is occupied by more than one species. On the basis of sources of their nutrition, organisms occupy a specific position in the food chain called their trophic level. For example, in a grassland ecosystem, rabbits and insects occupy the same trophic level, while both are different species. Therefore one trophic contains more than one species and is a functional level of different species rather than only one. Thus the trophic level cannot be represented by a species.
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 |
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.
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?
