Write the name of the organism that is referred to as the 'Terror of Bengal'.


Water hyacinth (Eichhornia crassipes) is referred to as the 'Terror of Bengal'.

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Depletion of which gas in the atmosphere can lead to an increased incidence of skin cancers

  • ozone

  • ammonia

  • methane

  • methane


A.

ozone

Ozone is found in the stratosphere acts as a shield absorbing ultraviolet radiation from the sun. So, its depletion can lead to an incidence of skin cancers. 

Ozone is found in the stratosphere acts as a shield absorbing ultraviolet radiation from the sun. So, its depletion can lead to an incidence of skin cancers. 

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Which of the following statements is correct

  • Catalytic converter can separate particulate matter of diameter less than 2.5 micrometers.

  • Histones are acidic in nature that forms core for DNA packaging.

  • Lactobacillus is not present in dough used in idli formation.

  • Template with polarity 5' 3' has continuous DNA replication.


B.

Histones are acidic in nature that forms core for DNA packaging.

According to Central Pollution Control Board (CPCB), particulate size 2.5 micrometers or less in diameter (PM 2.5) are responsible for causing the greatest harm to human health. These fine particulates can be inhaled deep into the lungs and can cause breathing and respiratory symptoms, such as irritation, inflammations and damage to the lungs and premature deaths.

According to Central Pollution Control Board (CPCB), particulate size 2.5 micrometers or less in diameter (PM 2.5) are responsible for causing the greatest harm to human health. These fine particulates can be inhaled deep into the lungs and can cause breathing and respiratory symptoms, such as irritation, inflammations and damage to the lungs and premature deaths.


Joint Forest management Concept was introduced in India during

  • 1970s

  • 1980s

  • 1990s

  • 1990s


B.

1980s

The Joint Forest management Concept was introduced in 1980s by the Government of India to work closely with the local communities for protection and management of forests.

The Joint Forest management Concept was introduced in 1980s by the Government of India to work closely with the local communities for protection and management of forests.

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Give reasons why:
a. Most zygotes in angiosperms divide only after certain amount of endosperm is formed.
b. Groundnut seeds are exalbuminous and castor seeds are albuminous.
c. Micropyle remains as a small pore in the seed coat of a seed.
d. Integuments of an ovule harden and the water content is highly reduced, as the seed matures.
e. Apple and cashew are not called true fruits.


a. Development of embryo depends upon the amount of endosperm present in the nucleus, as the embryo obtain its nutrition from the endosperm only. The cells of the endosperm tissue are filled with reserve food materials and provide nourishment to the developing embryo.

b. Utilization of the endosperm vary among plants, in some plants endosperm, gets exhausted or used up and produce exalbuminous seeds e.g groundnut.
In plants like castor some part of the endosperm persist in the seeds and are used during seed germination, these seeds are termed as albuminous

c. Seeds are covered by a hard covering called as integument, except at the top part of seed called as micropyle. Mycropyle helps in the entry of O2 and H2O during seed germination. Pollen tube enters the ovary through the micropyle. 

d. Maturation of seed is preceded by reduction in water content and increase hardening of integuments. Reduced content of water makes the seed metabolically slow and dry. Then embryo enters into dormancy stage. When seeds are subjected to adequate moisture, oxygen and suitable temperature they start to grow.

e. Maturation of ovules into seed and development of ovary into fruit occur simultaneously. When fruit develops from thalamus rather than from ovary are termed as false fruit.

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Public all over India is very much concerned about the deteriorating air quality in large parts of North India. Alarmed by this situation the Resident’s Welfare Association of your locality organised an awareness programme entitled ‘Bury not burn’. They invited you, being a biology student to participate.
(a) How would you justify your arguments that promote burying and discourage burning?
(Give two reasons)
(b) With the help of flow charts, one for each practice, depict the chain of events that follow.


(a) Following arguments can be put forward to promote burying and discourage burning:
(i) When we burn wastes, pollutants such as carbon dioxide,NO2 , SO2 , etc. are released in the atmosphere. These
pollutants damage the environment. Due to burning, smoke is released into atmosphere which causes
problems like asthma, emphysema, etc.
(ii) Burying the waste does not have any harmful effect in fact when we bury organic wastes, the soil becomes
enriched with nutrients.
(b) The solid wastes are of two types:
Biodegradable wastes These can be degraded by the microbes, e.g. organic waster paper, etc.
Non-biodegradable wastes These cannot be degraded by the microbes and can remain as such for long periods,
e.g. plastic.
Flow charts depicting effects of burying and burning are:



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