Tag: evs - i

Questions Related to evs - i

The lower part of exosphere contains

  1. Carbon zone

  2. Ozone zone

  3. Nitrogen zone

  4. Helium zone


Correct Option: D
Explanation:

Exosphere is the outer fringe of Earth's atmosphere, which extends some 20000 miles from the planet. It's dominant element is hydrogen and its temperature ranges from $200^0 F$ to $1000^0 F$. The lower part of exosphere contains abundance of helium besides hydrogen and is called as “helium zone”. Hence, option D is correct.

Biologists observe 5th June as

  1. Darwin birthday

  2. World environment day

  3. World population day

  4. World hygiene


Correct Option: B
Explanation:

5th June every year is observed as World Environment Day. This is to ensure awareness among people for the conservation and enhancement of the environment that forms a very integral part of our ecosystem.

So, option B is the correct answer.

An earthworm's niche is described by the statement that

  1. Earthworms are decomposers who live in the soil.

  2. Earthworms eat decaying organic matter.

  3. Earthworms are usually found living in the soil.

  4. Earthworms are used as food by some birds.

  5. Earthworms help the soil by aerating it.


Correct Option: A
Explanation:

Niche refers to the totality of an organism’s adaptations, its mode of use of available resources, and the lifestyle in its community. It includes the mode of consumption of materials in its environment as well as its interactions with other organisms. Habitat portion of earthworm's fundamental niche refers to the soil while its role as decomposer is the realized niche. Thus, the correct answer is A.

Interaction of species with the environment is known as

  1. Ecosystem

  2. Autecology

  3. Synecology

  4. Community


Correct Option: B
Explanation:

Group of same species in a given area is called population and interaction of population with environment is called Autoecology. So the correct option is " Autoecology"

Which one of the following is the region of cold temperature? 

  1. Mesosphere

  2. Thermosphere

  3. Ionosphere

  4. Exosphere


Correct Option: A
Explanation:
A. Mesosphere is the layer just above the stratosphere and extends from 50-85 km. Temperature is about -90° C in this region.
B. Thermosphere is the layer above the mesosphere. Ultraviolet radiations can penetrate this layer and causes photodissociation of molecules. Temperature increases in this region.
C. Ionosphere is the region of upper atmosphere of Earth that extends from 60-1000 km. Ionization by solar radiation occurs in this region.
D. Exosphere is the outermost layer of Earth's which hardly contains air.
Hence,the region of cold temperature is Mesophere.
So, the correct answer is 'Mesophere'.

Food web is constituted by

  1. Various interlinked food chains in a community

  2. Relationship between animals and plants

  3. Relationship between organisms and their environment

  4. Relationship between animals, plants and microbes


Correct Option: A
Explanation:
A food chain is series of plants/animals which are interrelated in the form of organism being eaten as food by the other. Food web is constituted by various interlinked and interdependent food chains in a community. It is also called as consumer-resource system. Ecosystem consists of living organisms and their abiotic environment. 
Thus, the correct answer is 'Various interlinked food chains in a community.'

In general, food webs consist of producers, consumers, and decomposers.

  1. True

  2. False

  3. Either

  4. Neither


Correct Option: A
Explanation:
Food web is an interconnected network of many food chains. In a food web, an organism occupies more than one trophic level. It may feed on different organisms of lower trophic levels and may get eaten itself by organisms of higher trophic levels. Food chain in turn, is a series of organisms which eat one and get eaten by other. A food chain comprises of different organisms at subsequent trophic levels. Autotrophs being producers occupy the lowest trophic level while consumers and decomposers occupy higher trophic levels. So, a food web consists of producers, consumers and decomposers with each occupying a particular trophic level.
Hence, the statement given in the question is correct.
So, the correct answer is 'True'.

Food web ensures survival of all types of trophic levels.

  1. True

  2. False

  3. Either

  4. Neither


Correct Option: A
Explanation:
Food web is a mesh like network of food chains which are interconnected. In a food web, an organism occupies more than one trophic level. It feeds on the organisms of lower trophic levels and is also eaten by other organisms of higher trophic levels. Thus all organisms at different trophic levels get food in a food web which ensures their survival. 
Hence, the statement given in the question is correct.
So, the correct answer is 'True'.

An example of a producer in the aquatic food web would be

  1. Duckweed

  2. Ducks

  3. Fish

  4. Insects


Correct Option: A
Explanation:
Producers are the green plants which convert light energy into chemical energy and prepare their own food. They are autotrophic component of an ecosystem. They are green plants and are photosynthetic. Their kind varies with the type of ecosystem. In an aquatic ecosystem, producers will be aquatic plants. For example, Duckweed also known as water lenses. These are flowering aquatic plants which keep floating on the surface of water. Since these plants are photosynthesising, they are producers in an aquatic food web.
So, the correct answer is 'Duckweed'.