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In a given food chain, suppose the amount of energy at fourth trophic level is 5 kJ, what will be the energy available at the producer level ?
Grass → Grasshopper → Frog → Snake → Hawk
  • a)
    5 kJ
  • b)
    50 kJ
  • c)
    500 kJ
  • d)
    5000 kJ
Correct answer is option 'D'. Can you explain this answer?

Surbhi Gupta answered
According to 10 percent law, 90% of the energy captured from the previous trophic level is lost to the environment and only 10 percent is made available to the next trophic level.

In this food chain, at the 4th trophic level, 5 kJ energy is available to the snake

⇒ Energy available to Frog = 10% of 50 kJ

⇒ Energy available to Grasshopper = 10% of 500 kJ

⇒ Energy available to Grass = 10% of 5000 kJ.

Which group of organisms are not constituents of a food chain?
(i) Grass, lion, rabbit, wolf
(ii) Plankton, man, fish, grasshopper
(iii) Wolf, grass, snake, tiger
(iv) Frog, snake, eagle, grass, grasshopper
  • a)
    (i) and (ii)
  • b)
    (iii) and (iv)
  • c)
    (ii) and (iii)
  • d)
    (i) and (iv)
Correct answer is option 'C'. Can you explain this answer?

Krishna Iyer answered
The organisms in an ecosystem are related through food requirements. This relationship is called food chain. In option (i) grass is eaten by rabbit, rabbit is consumed by wolf and lion eats wolf. In option (iv) grasshopper eats grass, frog eats grasshopper, snake eats frog and eagle consumes snake. In option (ii) grasshopper is found in terrestrial ecosystems not aquatic ecosystems. In option (iii) there is no herbivore animal to consume grass. Thus, the correct answer is option C.

A food chain comprising birds, green plants, fish and man. The concentration of harmful chemical entering the food chain will be maximum in
  • a)
    green plants
  • b)
    man
  • c)
    birds
  • d)
    fish
Correct answer is option 'B'. Can you explain this answer?

Avinash Patel answered
  • A food chain comprising birds, green plants, fish and man.
  • Food chain in ecology, the sequence of transfers of matter and energy in the form of food from one organism to another organism.
  • Food chains intervined locally into a food web because most organisms consume more than one type of animal or plant.
  • Each level of a food chain represents a different trophic level.
  • Humans are to be present at the top of the food chain because they eat all kinds of plants and animals.
  • The human food chain starts with plants.
  • Humans are dominant consumers.
  • They affect food webs through energy production and agriculture, pollution, habitat destruction, overfishing and hunting it affect both soil and aquatic ecosystem.

If a grasshopper is eaten by a frog, then the energy transfer will be from
  • a)
    producer to decomposer
  • b)
    producer to primary consumer
  • c)
    primary consumer to secondary consumer
  • d)
    secondary consumer to primary consumer
Correct answer is option 'C'. Can you explain this answer?

Anup mishra answered
The energy transfer in this scenario would be from a primary consumer (grasshopper) to a secondary consumer (frog). The grasshopper is considered a primary consumer because it eats plants, which are producers. When the frog eats the grasshopper, it is consuming the energy that was obtained by the grasshopper from the plants it ate. Therefore, the energy transfer is from a primary consumer to a secondary consumer.

Which of the following statements about food chain and energy flow through ecosystem is false?
  • a)
    Food webs include two or more food chains
  • b)
    All organisms that are not producers are consumers
  • c)
    A single organism can feed at several trophic levels
  • d)
    Detritivores feed at all trophic levels except the producer level
  • e)
    The lower the trophic level at which an organism feeds, the more energy available
Correct answer is option 'D'. Can you explain this answer?

Gaurav Kumar answered
There are many food chains which are interconnected to form the food web and so one organism can feed at different trophic levels in the different food chain. There is a 0gradual decrease in the energy of the increasing trophic levels due to the loss of energy with each transfer. The producers are the organisms which can synthesize food and the organisms which feed on the other sources are known as consumers. The detrivores are the organisms which feed on the dead matter of the organisms which belong to all the trophic levels. 

Excessive exposure of humans to UV rays results in
(i) damage to immune system
(ii) damage to lungs
(iii) skin cancer
(iv) peptic ulcers
  • a)
    (i) and (ii)
  • b)
    (ii) and (iv)
  • c)
    (i) and (iii)
  • d)
    (iii) and (iv)
Correct answer is option 'C'. Can you explain this answer?

Madara Uchiha answered
UV Rays as the name suggests Ultra Violent rays causes a lot of harm to our body and to our environment like :-
1. temporary/permanent blindness
2. skin cancer
3. faster evaporation of water which leads to drying of leaves(Forest Fire)
4. infrastructural damage
and so on

Excessive exposure of humans to UV-rays results in
(i) damage to immune system
(ii) damage to lungs
(iii) skin cancer
(iv) peptic ulcer
  • a)
    (i) and (ii)
  • b)
    (ii) and (iv)
  • c)
    (i) and (iii)
  • d)
    (iii) and (iv)
Correct answer is option 'C'. Can you explain this answer?

Gaurav Kumar answered
UV rays or ultraviolet rays can affect human health in many ways like causing skin cancer or weakening immune system. Excessive exposure to UV rays can lead to skin cancer because the UV rays cause damage to the DNA in skin cells. 

In the garden ecosystem, which of the following are producers?
  • a)
    Insects
  • b)
    Snakes
  • c)
    Grasses
  • d)
    Rabbits
Correct answer is option 'C'. Can you explain this answer?

Green plants (grasses) are autotrophic. They perform photosynthesis by using solar energy to synthesize their own food. Hence they are the producers in an ecosystem.

First link in any food chain is usually green plants because
  • a)
    they are widely distributed
  • b)
    they are fixed at one place in the soil
  • c)
    they alone have the capacity to synthesise food using sunlight
  • d)
    there are more herbivores than carnivores
Correct answer is option 'C'. Can you explain this answer?

Crafty Classes answered
Why are green plants usually the first link in any food chain?

Green plants are usually the first link in any food chain because:


  • Capacity to synthesize food: Green plants are the primary producers in an ecosystem. They have the ability to synthesize their food through a process called photosynthesis, using sunlight, water, and carbon dioxide. This allows them to convert solar energy into chemical energy in the form of glucose.


  • Provide energy: Green plants serve as a source of energy for other organisms in the food chain. They convert sunlight energy into organic matter, which is consumed by herbivores.


  • Abundance: Green plants are widely distributed and abundant in most ecosystems. They can be found in various habitats, including terrestrial and aquatic environments. Their abundance ensures a stable and continuous food supply for other organisms.


  • Fixed in one place: Unlike animals, green plants are fixed in one place due to their root systems. This allows them to establish a stable base for the food chain, as they act as a foundation for the whole ecosystem.


Overall, green plants hold a crucial role in the food chain as they provide energy, are widely distributed, have the capacity to synthesize food, and form the primary link in the transfer of energy through the ecosystem.

Which of the following is an autotroph?
  • a)
    Lion
  • b)
    Insect
  • c)
    Tree
  • d)
    Mushroom
Correct answer is option 'C'. Can you explain this answer?

Anju Mala answered
Autotrophs means organisms who prepare their own food and heterotrophs are organisms who depend on autotrophs directly or indirectly and as you may be knowing that tree or plants prepare their own food by the process of photosynthesis , so c is the correct answer

An ecosystem includes
  • a)
    all living organisms
  • b)
    non-living objects
  • c)
    both living organisms and non-living objects
  • d)
    sometimes living organisms and sometimes non-living objects
Correct answer is option 'C'. Can you explain this answer?

An ecosystem is an interaction between the living organism (biotic component) and their physical environment (abiotic componenet). Thus, the correct answer is option C.

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