Tag: ecosystems

Questions Related to ecosystems

Which bacteria can flourish and carry out decomposition of organic matter, both in presence and absence of oxygen?

  1. Facultative Bacteria

  2. Aerobic Bacteria

  3. Anaerobic Bacteria

  4. Blue green algae


Correct Option: A

'Aerobic' decomposition takes place in

  1. Two stages

  2. Three stages

  3. Four Stages

  4. Five stages


Correct Option: A

In first stage of aerobic decomposition, carbonaceous matter is being

  1. Reduced

  2. Oxidized

  3. Formed

  4. Decomposed


Correct Option: B

The plant parts when fully decomposed by microorganism and mixed in the soil is caIled as

  1. Litter

  2. Duff

  3. Humus

  4. All of the above


Correct Option: C
Explanation:

Humus is a dark-brown or black organic substance made up of decayed plant or animal matter which are fully decomposed by microorganisms like bacteria. Humus provides nutrients for plants and increases the ability of soil to retain water. It has a characteristic black or dark brown color and is organic due to an accumulation of organic carbon. 

Therefore, the correct answer is option C.

Humus is 

  1. Dead and decayed organic matter

  2. Living matter

  3. Fertilizers

  4. Living animal, plants and microbes


Correct Option: A
Explanation:

Humus is dark, organic material that forms in soil when plant and animal matter decays. When plants drop leaves, twigs, and other material to the ground, it piles up. This material is called leaf litter. When animals die, their remains add to the litter. The thick brown or black substance that remains after most of the organic litter has decomposed is called as humus. Humus contains many useful nutrients for healthy soil. 

The slow rate of decomposition of fallen Iogs in nature is due to their

  1. Anaerobic environment around them

  2. Low cellulose content

  3. Low moisture content

  4. Poor nitrogen content


Correct Option: C
Explanation:

Photosynthetically fixed carbon is eventually degraded by micro-organisms and two major forms of carbon known as methane and carbon dioxide. The micro-organisms breakdown the complex compounds of dead protoplasm of producers compounds of dead protoplasm of producers and consumers absorb some of the decomposition products and release simple substances. The slow rate of decomposition of fallen logs in nature is because of low moisture content.

Therefore, the correct answer is option C.

What does the term 'NPK' mean?

  1. Nitrate, potash and calcium

  2. Nitrogen, phosphate and chromium

  3. Nitrogen, phosphorus and potassium

  4. Nitrate, protein and vitamins.


Correct Option: C
Explanation:

Nitrogen(N). phosphorous(P), potassium (K) are used to label fertilizers based on the relative content of these chemicals.

Humus is an example of

  1. Soil structure

  2. Cryustalloids

  3. Organic colloids

  4. None of these


Correct Option: C
Explanation:
  • Humus particles are tiny pieces of organic matter and are known as Organic Colloids.
  • Humus is important because it retains moisture in the soil, loosens the soil permitting better aeration and drainage, and encourages the increase of soil organisms which help make nutrients available to plants.
  • Hence Humus is an example of organic colloids.
  • So, the correct answer is 'Organic colloids'.

Microorganism act upon a dead plant to produce

  1. Humus

  2. Mushroom

  3. Wood

  4. Sand


Correct Option: A
Explanation:

Dead plants and animals are degraded in soil by decomposing bacteria and fungi. The material formed after the decomposition process is called humus. Humus is very rich in nutrients and black in colour. Greater the amount of humus more is the soil productivity. Thus, the correct answer is option A.

Mark the correct statement
a) Microbes helps in decomposition process
b) They help in maintaining biogeochemical cycle
c) Microbes only helps in carbon cycle, they don't have any role in nitrogen cycle

  1. a, b

  2. a, c

  3. b, c

  4. All


Correct Option: A
Explanation:

Microbes play important role in our lives and in the environment. They help in the decomposition process and in maintaining the biogeo-chemical cycles like carbon and nitrogen cycles.

So, the correct answer is 'a,b'