BIO 102 | Study Mode

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Question 161
A
India
B
France
C
USA
D
Britain.
Explanation
Depletion in the concentration of ozone over a restricted area as spring time decline over Antartica is called ozone hole. Depletion of ozone is due to action of sunlight over pollutants which release chemicals (e.g., chlorine) that destroy ozone. The major are chloroflouroarbons (14% of total depletion), nitrogen oxides (3.5% deplection sulphur dioxide, halon, carbon tetrachloride, methyl chloroform, chlorine, etc. Major contributor of these gases is USA.

Correct option: C
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Question 162
A
mutualism
B
commensalism
C
coperation
D
co-evolution.
Explanation
Co-evolution can occur in any interspecific relationship like symbiosis or mutualism. The relation between an entomophilous flower and pollinating insect shows co-evolved mutualism. In this the plant depends exclusively on the insect for pollination and the insect relies on the plant for food.

Correct option: D
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Question 163
A
Allens law
B
Gauses hypothesis
C
Dollos rule
D
Weismans theory.
Explanation
Interspecific competition is rivalry amongst members of different species. The severity of competition depends upon similarity in the requirement of food and shelter. Every type of organism has a particular niche; no two organisms can live in same niche. One of the two is eliminated. This phenomenon is called Gause hypothesis of competitive exclusion. Different organisms develop different types of variations in order to exploit niches, e.g. 14 species of Finches in Galapagos Islands.

Allens law states that there is tendency of smaller extremities like ear, nose, tail etc in animals living in colder climate.

Weismans germplasm theory was the ultimate blow-to discards lamarckism.

Dollos law proposed that evolution is irreversible.


Correct option: B
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Question 164
A
first trophic level (T1)
B
second trophic level (T2)
C
third trophic level (T3)
D
fourth trophic level (T4).
Explanation
Trophic structure of ecosystem is a type of producer-consumer arrangement, in which each food level is called trophic level and the graphical representation of trophic structure of ecosystem constitutes ecological pyramids. The green plants are producers and represent the first trophic level (T1).

So bamboo plant is the first trophic level (T1).


Correct option: A
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Question 165
A
mutualism
B
commensalism
C
co-operation
D
co-evolution
Explanation
Co evolution may be defined as, evolution in two species that interact extensively with one another so that each acts as a major force of natural selection on the other. When two species or two populations of a single species interact extensively, each exerts strong selective pressures on the other. When one evolves a new feature or modifies an old one, the other generally evolves new adaptations in response.

This constant, mutual feedback between two species is called co evolution. Animal-pollinated flowers must attract useful pollinators and frustrate undesirable visitors eating nectar or pollen without fertilizing the flower in return. The animals, in turn, have been under selective pressures to locate flowers quickly and identify the flowers that can provide them with sufficient nutrition in terms of nectar or pollen with minimum expenditure of energy. So that the entomophilous flower and the insects have coevolved.


Correct option: D
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Question 166
A
brain
B
heart
C
teeth
D
kidney
Explanation
Flourides are given out during refining of materials. Flourides cause flourosis. It is a disease which is defined by mottling of teeth, abnormal bones that are liable to fracture because fluorine replaces Ca2+ and makes the bones brittle. Flouride pollution is a serious problem in many districts of Rajasthan, where excess of flouride in water adversely affects the health of man. Many villagers have aged prematurely or became hunch backs.

Correct option: C
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Question 167
A
heavy metals
B
faecal matter
C
industrial effluents
D
pollen of aquatic plants
Explanation
E. coli is the most common indicator of water pollution. It naturally occurs in the intestines of human beings and animals. They are commonly found in sewage and if E. coli is detected in water then it indicates fecal contamination. So if E. coli are detected in drinking water it indicates a serious health risk and that water-should not be used for drinking.

Correct option: B
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Question 168
A
symbiotic relationship
B
ectoparasitism
C
endoparasitism
D
decomposers
Explanation
In mutalism or symbosis both the organisms in association are mutually benefitted and further this association is obligatory, i.e., necessary for existence of both organisms. Mycorrhiza is a example of symbiosis. It is association between roots of higher plants and fungal hyphae. The fungal hyphae supply water and nutrients to the plant and in turn get food form the plant. So both the organism are mutually benefitted.

Correct option: A
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Question 169
A
high fertility, low or rapidly fall rate, rapid population growth and age distribution
B
high fertility, high density, mortality rate and a very young age
C
high infant mortality, low fertility population growth and a very distribution
D
high mortality, high density, uneven growth and a very old age distribution.
Explanation
In developing countries the conditions are becoming better for survival of human beings. So the mortality rate or the number of individuals dying per unit of time is low.

Mortality or the average number of individuals produced by a population in a unit of time is high. So that there is rapid population growth and there are more individuals in the pre-reproductive age group. So there is young age distribution.


Correct option: A
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Question 170
A
a species which makes up only a small proportion of the total biomass of a community, yet has a huge impact communitys organization and s
B
a common species that has plenty of biomass yet has a fairly low impact on the community organization
C
a rare species that has minimal impact on the biomass and on other species in the community
D
a dominant species that constitutes a large proportion of the biomass and which affects many other species.
Explanation
Keystone species are those species which has significant and disproportionately large influence on the community structure and characteristics. It has often considerably low abundance and biomass as compared to dominant species. Removal of such species causes serious disruption in structure and function of community.

Correct option: A

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