Download App

STD 12 - 12. ecosystem — BIOLOGY STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceBIOLOGYSTD 12 - 12. ecosystem1 Mark
MCQ
The breakdown of detritus into smaller particles by earthworm is a process called
  • A
    humification
  • ✓
    fragmentation
  • C
    mineralisation
  • D
    catabolism.
✓

Answer

Correct option: B.
fragmentation
b
(b) : Decomposition is the process in which decomposers break down complex organic matter into inorganic substances like carbon dioxide, water and nutrients. The important steps in the process of decomposition are fragmentation, leaching, catabolism, humification and mineralisation. Detritivores ($e.g.$, earthworm) break down detritus into smaller particles. This process is called fragmentation. By the process of leaching, water­ soluble inorganic nutrients go down into the soil horizon and get precipitated as unavailable salts. Bacterial and fungal enzymes degrade detritus into simpler inorganic substances. This process is called as catabolism. Humification and mineralisation occur during decomposition in the soil. Humification leads to accumulation of a dark coloured amorphous substance called humus that is highly resistant to microbial action and undergoes decomposition at an extremely slow rate. The humus is further degraded by some microbes and release of inorganic nutrients occur by the process known as mineralisation.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "M.C.Q (0.5 Marks)" from STD 12 - 12. ecosystem→STD 12 - 12. ecosystem — all question types→BIOLOGY STD 12 Science question papers→Rajasthan Board STD 12 Science question papers→Rajasthan Board question paper generator→

Similar questions

Identify the correct order of organisation ofgenetic material from largest to smallest.
→
Normal maize has starchy seeds which remain smooth when dry. A mutant form has sugary seeds which go crinckled when dry. When a mutant was crossed with a normal plant, an $F_1$ was produced which had smooth seeds. What would be the relative ratios of the different seed types, if the $F_1$ was allowed to self
→
Match Column $I$ with Column $II$ and choose correct option
Column-$I$ Column-$II$
$a.$ Aestivation $(i)$ Over wintering
$b$. Hibernation $(ii)$ Over summer
$c.$ Diapause $(iii)$ Suspended development in zooplanktons
→
The cutting of $DNA$ by restriction endonucleasesresults in the fragments of $DNA$. These fragments can be separated by a technique known as ......
→
Which of the following hormone controls sertoli cells-
→
$A $ : Biodiversity of the prokaryotes cannot be estimated.

$R$ : Conventional taxonomic methods are not suitable for identification and characterisation of microbes.

→
DNA finger-printing refers to:
→
Assertion: Histamine is related with allergic and inflammatory reactions.

Reason: Histamine is a vasodilator.

→
Amniocentesis involves the analysis of
→
Mating of an organism to a double recessive in order to determine whether it is homozygous or heterozygous for a character under consideration, is called
→