Define ecological pyramids. Name the different types of ecological pyramids. |
OR |
Describe the methods adopted by the Delhi Government to control the vehicular air pollution in Delhi. |
(i) Name the events of sexual reproduction. |
(ii) Describe the post-fertilisation changes in a flower. |
What are the functions of mRNA and tRNA? Which anticodons will be required to recognize following codons? |
(i) AAU |
(ii) UAU |
(iii) CGA |
(iv) GCA |
When a cross is made between tall plant yellow seeds (TtYy) and tall plant with green seed (Ttyy), what proportion of Phenol type in the offspring could be expected to be: |
(i) tall and green (ii) dwarf and green |
OR |
In peas, tallness is dominant over dwarfiiess, and red colour flowers is dominant over the white colour. When a tall plant bearing red flowers was pollinated by a dwarf plant bearing white flowers, the different phenotypic groups were obtained in the progeny in numbers, mentioned against them. |
(i) Tall, Red = 138 |
(ii) Tall, White = 132 |
(iii) Dwarf, Rdd = 136 |
(iv) Dwarf, White = 128 |
A bright student of class XI, under peer pressure started taking drugs. He started neglecting studies, misbehaving with parents and friends in school. |
The principal of school counselled him but have no effect. His parents took him to a rehabilitation center. After a few months he came back recovered. |
(i) What is drug abuse? |
(ii) Name some commonly abused drugs and their sources. |
(iii) What should be the attitude of his parents after his return? |
(iv) What values did the principal reflect through his initiative? |
Describe the functions of the following: |
(i) Epididymis |
(ii) Vas deferens |
(iii) Seminiferous tubules |
(iv) Vagina |
(v) Trophoblast |
OR |
Study the given figure. |
(i) Pick out and name the cells that undergo spermiogenesis. |
(ii) Name 'A' and 'B' cells. What is the difference between them with reference to the number of chromosome? |
(iii) Pick out and name the motile cells. |
(iv) What is 'F' cell? Mention its function. |
(v) Name the structure of which the given diagram is apart. |
Name a disorder, give the karyotype and write the symptoms where a human female suffers as a result of an additional copy of chromosome number 21 (trisomy). |
OR |
(i) Write the scientific name of the bacterium used by Frederick Griffith in his experiment. |
(ii) How did he prove that transforming principle is responsible for transformation of the non-virulent strains of bacteria into the virulent form? |
(iii) State the biochemical nature of the transforming principle. |
(iv) Give the name of the scientists who proved it. |
Define ecological succession. Give four differences between seral stage and climax community during succession. |
OR |
Write an account of habitat fragmentation and its effect on biodiversity. |
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