Q. No.A sedentary sea anemone gets attached to the shell lining of a hermit crab. The association is:
1. Symbiosis
2. Commensalism
3. Amensalism
4. Ectoparasitism
A biologist studied the population of rats in a barn. He found that the average natality was 250, average mortality 240, immigration 20 and emigration 30. The net increase in population is:
| 1. | 15 | 2. | 05 |
| 3. | zero | 4. | 10 |
According to Darwin, organic evolution is due to:
| 1. | Interspecific competition. |
| 2. | Competition within closely related species. |
| 3. | Reduced feeding efficiency in one species due to the presence of interfering species. |
| 4. | Intraspecific competition. |
People who have migrated from the planes to an area adjoining Rohtang Pass about six months back:
| 1. | Have more RBCs and their haemoglobin has a lower binding affinity to 02 |
| 2. | Are not physically fit to play games like football |
| 3. | Suffer from altitude sickness with symptoms like nausea, fatigue, etc. |
| 4. | have the usual RBC count but their haemoglobin has a very binding affinity to 02 |
What type of human population is represented by the following age pyramid?
1. Stable population
2. Declining population
3. Expanding population
4. Vanishing population
| 1. | Human foetus developing inside the uterus draws nourishment from the mother |
| 2. | Head louse living on the human scalp as well as laying eggs on human hair |
| 3. | The cuckoo (koel) lays its eggs in a crow's nest |
| 4. | The female Anopheles bites and sucks blood from humans |
Study the four statements (a–d) given below and select the two correct ones out of them:
| (a) | A lion eating a deer and a sparrow feeding on grain are ecologically similar in being consumers |
| (b) | Predator starfish Pisaster helps in maintaining species diversity of some invertebrates |
| (c) | Predators ultimately lead to the extinction of prey species |
| (d) | Production of chemicals such as nicotine and strychnine by plants is metabolic disorder |
The two correct statements are:
1. a and d
2. a and b
3. b and c
4. c and d
A country with a high rate of population growth took measures to reduce it. The figure below shows age-sex pyramids of populations. A and B are twenty years apart. Select the correct interpretation about them:
Interpretations
| 1. | 'A' is more recent and shows a slight reduction in the growth rate |
| 2. | 'B' is an earlier pyramid and shows stabilised growth rate |
| 3. | 'B' is more recent showing that the population is very young |
| 4. | 'A' is the earlier pyramid and no change has occurred in the growth rate |
The table below gives the populations(in thousands) of ten species(A--J) in four areas (a-d) consisting of the number of habitats given within brackets against each. Study the table and answer the question as follows:
which area out of a to d shows maximum species diversity?
1. b
2. c
3. a
4. d
The population of an insect species shows an explosive increase in numbers during the rainy season followed by its disappearance at the end of the season. What does this show?
| 1. | S-shaped or sigmoid growth of this insect |
| 2. | the food plants mature and die at the end of the rainy season |
| 3. | Its population growth curve is of J-type |
| 4. | The population of its predators increases enormously |
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