Decomposition MCQs and Answers

Are you looking for Decomposition MCQs and Answers for medical entrance examinations? If yes, these are some most important multiple choice questions and answers on NCERT Class-12 Biology, Chapter-14 (Ecosystem).

Here we composed these Decomposition MCQs and Answers after reading the chapter on Ecosystem from the NCERT book on Class 12 Biology. The questions are topics-wise and the students can relate the questions easily to the most important topics of this chapter.

Decomposition MCQs and Answers

1. Which organism is said to be a farmer’s friend?

a) Rat

b) Earthworm

c) Bat

d) Leopard

Answer: b


2. Which are the organisms called those who are responsible for the break down complex organic matter into inorganic substances?

a) Decomposers

b) Producers

c) Consumers

d) Herbivores

Answer: a


3. What is the process of break down complex organic matter into inorganic substances called?

a) Organization

b) Decomposition

c) Production

d) Consumption

Answer: b


4. What are the complex organic remains such as dead animal remains, dead plant remains, and fecal matter called?

a) Humus

b) Mucus

c) Excreta

d) Detritus

Answer: d


5. Which organisms carry out the fragmentation of detritus?

a) Sponges

b) Vertebrates

c) Detritivores

d) Zooplankton

Answer: c


6. Which of the following is an example of detritivore?

a) Monkey

b) Termites

c) Elephant

d) Flat-worm

Answer: b


7. What is the process of secretion of digestive enzymes by decomposers to convert insoluble complex organic molecules into simple soluble organic and inorganic molecules called?

a) Fragmentation

b) Decomposition

c) Humification

d) Catabolism

Answer: d


8. What is the process called when detritivores feed on larger pieces and leave smaller fragments behind?

a) Leaching

b) Catabolism

c) Fragmentation

d) Mineralization

Answer: c


9. What is the process of the formation of a dark-colored amorphous substance called?

a) Leaching

b) Catabolism

c) Fragmentation

d) Humification

Answer: d


10. What is the dark amorphous organic matter rich in cellulose and lignin that is highly resistant to any microbial action and decomposes at a slower rate called?

a) Fragments

b) Enzymes

c) Humus

d) Minerals

Answer: c


11. What is the percolation of the soluble substances formed due to decomposition called?

a) Humification

b) Leaching

c) Mineralization

d) Catabolism

Answer: b


12. Which substances are formed along with humus due to the decomposition process?

a) Organic substances

b) Minerals

c) Inorganic substance

d) Fragments

Answer: c


13. What is the process of release of inorganic substances both minerals and non-minerals from organic matter called?

a) Fragmentation

b) Mineralization

c) Humification

d) Leaching

Answer: b


14. How many steps are involved in the process of decomposition?

a) 10

b) 2

c) 8

d) 5

Answer: d


15. What does decomposition depend on?

a) Oxygen

b) Nitrogen

c) Ammonia

d) Carbon monoxide

Answer: a


16. Along with oxygen what are the other components decomposition depend on?

a) Oxygen

b) Chemical composition of detritus

c) Decomposers

d) Leaching

Answer: b


17. Along with oxygen what are the other components decomposition depend on?

a) Climatic conditions

b) Decomposers

c) Humification

d) Leaching

Answer: a


18. At what rate does decomposition occur when detritus is rich in nitrogen and sugars?

a) Slower

b) Faster

c) Moderate

d) Neutral

Answer: b


19. At what rate does decomposition occur when detritus is rich in lignin and chitin?

a) Faster

b) Neutral

c) Moderate

d) Slower

Answer: d


20. What environment is favorable for the process of decomposition?

a) Low temperature and anaerobic conditions

b) High temperature

c) Warm and moist

d) Watery

Answer: c


21. What environment is unfavorable for the process of decomposition?

a) Warm

b) Low temperature and anaerobic conditions

c) Moist

d) Having good humus

Answer: b


When materials decompose, they break down into smaller pieces. Decomposition is a natural process that happens to everything. It is the way the Earth recycles materials.

There are different types of decomposition. Some examples are:

Chemical decomposition: This is when a substance breaks down into smaller pieces through a chemical reaction.

Physical decomposition: This is when a substance breaks down into smaller pieces through physical means, such as grinding or crushing.

Biological decomposition: This is when living things, like bacteria and fungi, break down materials.

Here are some frequently asked questions about decomposition:

FAQs on Decomposition

Q: How long does it take for materials to decompose?

A: It depends on the material and the conditions. Some materials, like paper and leaves, decompose quickly. Others, like plastic and metal, take much longer.

Q: What happens to the material when it decomposes?

A: The material is broken down into smaller pieces. Some of the material may be used by bacteria and fungi, and some may be dissolved in water.

Q: Can decomposition be stopped?

A: No, decomposition is a natural process that happens to everything. However, you can slow it down by keeping materials dry and out of direct sunlight.

Have any other questions about Decomposition? Leave a comment below and we’ll do our best to answer them!

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