Tag: evs

Questions Related to evs

Mycorrhiza is a symbiotic associated of fungus with root system which helps in
A. absorption of water
B. mineral nutrition
C. translocation
D. gaseous exchange.

  1. Only A

  2. Only B

  3. Both A and B

  4. Both B and C


Correct Option: C
Explanation:
The roots of some higher plants are associated with fungal mycelia. Such an association is called mycorrhiza. It represents a mutualistic(symbiotic) association between the root system of higher plants and fundal hyphae. The fungal hyphae form a network around the young root and invade the root cells. The external hyphae greatly increase the surface area for absorption of minerals and water from a much larger volume of soil that perhaps the roots alone cannot do.
So, the correct answer is 'Both A and B'.

Litmus is obtained from

  1. Lichen

  2. Algae

  3. Fungi

  4. Protozoa


Correct Option: A
Explanation:

Litmus, was formerly prepared only in Holland, but at present is manufactured from various lichens in Italy, France and Britain. A peculiar blue coloring matter obtained from Roccella tinctoria, Acharius, and other lichens. Roccella tinctoria, or Orchilla weed, is a small, dry lichen, with a rounded, glaucous, nearly erect thallus, forked and subdivided into numerous branchy, roundish, gray, yellowish, or brownish threads; the apothecia are scattered, red and elevated; the disks are flat, caesius, pruinose, and as broad as the border.

Indicator plants which can be used to indicate atmospheric pollution by $SO _2$ are

  1. Lichens like Usnea

  2. Grassland like Deschampsia

  3. Moss like Sphagnum

  4. Climbers like Cucurbita


Correct Option: A
Explanation:

Sulphur dioxide is produced during combustion of fossil fuels, refining of petroleum and smelting of sulphur containing ores. Sulphur dioxide produces smog and acid rain. Sulphur dioxide causes membrane damage, destruction of chlorophyll, necrosis and water soaked appearance. Lichens are the most sensitive organisms to sulphur dioxide pollution and do not grow in areas with high levels of sulphur dioxides. Hence Lichens like Usnea are used as indicators of level of sulphur dioxide pollution.

A location with luxuriant growth of lichens on the trees indicated that the :

  1. Trees are heavily infested.

  2. Location is highly polluted.

  3. Location is not polluted.

  4. Trees are very healthy.


Correct Option: C
Explanation:

Lichens are sensitive to air pollution and hence they are absent in polluted areas. An extensive grwth of lichens indicate that the location is unpolluted.

So the correct option is C.

Pick up the wrong statement :

  1. Lichens are symbiotic association.

  2. Lichens are very good pollution indicators.

  3. Lichens do not grow in unpolluted areas.

  4. The algal component of lichen is known as phycobiont.

  5. The fungal component of lichen is known as mycobiot.


Correct Option: C
Explanation:

Lichens are very sensitive to sulphur dioxide pollution in the air and hence they don't grow in polluted areas. They are found in unpolluted areas.

So the incorrect statement is C.

Lichens are described as indicators of :

  1. Soil pollution

  2. Air pollution

  3. Water pollution

  4. Agricultural productivity


Correct Option: B
Explanation:
Lichen cannot survive in places with air pollution especially $SO _2$, if Lichens inhabit a particular area, it is an indication that the air is no or minimum pollutants
So, the correct answer is 'Air pollution'

Litmus is got naturally from

  1. Algae

  2. Fungi

  3. Lichens

  4. Protozoans.


Correct Option: C
Explanation:

Litmus is got naturally from different species of Lichens. It is used as pH indicator to check the acidity of a material.

Thus, the correct answer is option C.

In perfumery, the lichen species used are 

  1. Caledonia

  2. Evermia

  3. Snead

  4. Parmelia


Correct Option: B
Explanation:

In perfumery, two species of lichen are used, namely Evernia prunastri and Pseudevernia furfuracea. These are commonly called as oakmoss and treemoss respectively. Evernia prunastri is found on oak trees. 

Thus, the correct answer is 'Evernia.'

Intraspecific competition is strongest when the

  1. Reproductive rate is at its maximum

  2. Populations overlap in their ranges

  3. Species overlap in their distribution

  4. Population is at its carrying capacity


Correct Option: D
Explanation:

Competition present between the members of the same species compete for limited resources is called Intraspecific competitions. Intraspecific competition is affected not only by the type of competition but also by the type of resource. .

So the correct option is 'population is at its carrying capacity'.

Air quality indicator is

  1. Lichen

  2. Moss

  3. Algae

  4. None of the above


Correct Option: A
Explanation:

Lichens are mutualistic associations of a fungus and an alga or cyanobacterium and occur as crusty patches or bushy growths on trees, rocks and bare ground. 

Lichens are very sensitive to sulphur dioxide pollution in the air. Lichens are widely used as environmental indicators or bio-indicators. If air is very badly polluted with sulphur dioxide there may be no lichens present. Lichens are sensitive to sulphur dioxide, because their efficient absorption systems result in rapid accumulation of sulphur when exposed to high levels of sulphur dioxide pollution. The algal partner are most affected by the sulphur dioxide; chlorophyll is destroyed and photosynthesis is inhibited.