Question map
Not attempted Correct Incorrect ★ Bookmarked
Loading…
Q48 (IAS/2021) Environment & Ecology › Ecology & Ecosystem Basics › Ecosystem concepts Official Key

Which of the following are detritivores? 1. Earthworms 2. Jellyfish 3. Millipedes 4. Seahorses 5. Woodlice Select the correct answer using the code given below:

Result
Your answer: —  ·  Correct: C
Explanation

The correct answer is Option 3 (1, 3, and 5 only) because detritivores are heterotrophs that obtain nutrients by consuming detritus (decomposing plant and animal parts as well as feces).

  • Earthworms (1): They are classic detritivores that ingest soil and organic matter, breaking it down into nutrient-rich humus.
  • Millipedes (3): Unlike centipedes (which are predators), millipedes primarily feed on decaying leaves and other dead plant matter.
  • Woodlice (5): These terrestrial crustaceans feed predominantly on rotting wood and fungal growth, playing a vital role in decomposition.

In contrast, Jellyfish (2) are mostly carnivorous predators that use stinging cells to capture live plankton or small fish. Seahorses (4) are also predators, using their snouts to suck in small live crustaceans and larval fish. Since jellyfish and seahorses do not feed on dead organic waste, they are excluded, making Option 3 the only correct choice.

How others answered
Each bar shows the % of students who chose that option. Green bar = correct answer, blue outline = your choice.
Community Performance
Out of everyone who attempted this question.
68%
got it right
PROVENANCE & STUDY PATTERN
Guest preview
Don’t just practise – reverse-engineer the question. This panel shows where this PYQ came from (books / web), how the examiner broke it into hidden statements, and which nearby micro-concepts you were supposed to learn from it. Treat it like an autopsy of the question: what might have triggered it, which exact lines in the book matter, and what linked ideas you should carry forward to future questions.
Q. Which of the following are detritivores? 1. Earthworms 2. Jellyfish 3. Millipedes 4. Seahorses 5. Woodlice Select the correct answer usin…
At a glance
Origin: Mixed / unclear origin Fairness: Low / Borderline fairness Books / CA: 2/10 · 0/10
You're seeing a guest preview. The Verdict and first statement analysis are open. Login with Google to unlock all tabs.

This is a classic 'Applied Biology' question. While standard books (Shankar/NCERT) only explicitly list Earthworms, the question demands you apply the definition of 'Detritivore' (eater of dead organic matter) to eliminate obvious predators. It tests observation and common sense over rote memorization.

How this question is built

This question can be broken into the following sub-statements. Tap a statement sentence to jump into its detailed analysis.

Statement 1
Are earthworms detritivores (organisms that feed on decomposing organic matter)?
Origin: Direct from books Fairness: Straightforward Book-answerable
From standard books
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 1: Ecology > ii) Micro consumers - Saprotrophs (decomposers or osmotrophs) > p. 7
Presence: 5/5
“(ii) Micro consumers - Saprotrophs (decomposers or osmotrophs) • They are bacteria and fungi which obtain energy and nutrients by decomposing dead organic substances (detritus) of plant and animal origin. • The products of decomposition such as inorganic nutrients which are released in the ecosystem are reused by producers and thus recycled. • Earthworm and certain soil organisms (such as nematodes, and arthropods) are detritus feeders and help in the decomposition of organic matter and are called detrivores.”
Why this source?
  • Explicitly names earthworms as detritus feeders (detrivores).
  • Links earthworms to decomposition of organic matter and nutrient recycling.
Indian Economy, Vivek Singh (7th ed. 2023-24) > Chapter 11: Agriculture - Part II > Differences between Organic Farming and ZBNF: > p. 349
Presence: 4/5
“In organic farming, organic fertilizers and manures like compost, vermicompost, cow dung manure, etc. are used and added to farmlands from external sources. While in natural farming, neither chemical nor organic fertilizers are added to the soil. In fact, no external fertilizers are added to soil or given to plants whatsoever. In natural farming, decomposition of organic matter by microbes and earthworms is encouraged right on the soil surface itself, which gradually adds nutrition in the soil, over the period.”
Why this source?
  • Describes decomposition of organic matter by microbes and earthworms in farming practices.
  • Connects earthworm activity to generation of soil nutrition (vermicompost context).
FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 5: Geomorphic Processes > Biological Activity > p. 45
Presence: 3/5
“Further, bacteria and other soil organisms take gaseous nitrogen from the air and convert it into a chemical form that can be used by plants. This process is known as nitrogen fixation. Rhizobium, a type of bacteria, lives in the root nodules of leguminous plants and fixes nitrogen beneficial to the host plant. The influence of large animals like ants, termites, earthworms, rodents etc., is mechanical, but, it is nevertheless important in soil formation as they rework the soil up and down. In case of earthworms, as they feed on soil, the texture and chemistry of the soil that comes out of their body changes.”
Why this source?
  • Explains earthworms feed on soil and mechanically rework it, altering texture and chemistry.
  • Implies a role in processing organic material and contributing to soil formation.
Statement analysis

This statement analysis shows book citations, web sources and indirect clues. The first statement (S1) is open for preview.

Login with Google to unlock all statements.

Statement analysis

This statement analysis shows book citations, web sources and indirect clues. The first statement (S1) is open for preview.

Login with Google to unlock all statements.

Statement analysis

This statement analysis shows book citations, web sources and indirect clues. The first statement (S1) is open for preview.

Login with Google to unlock all statements.

Statement analysis

This statement analysis shows book citations, web sources and indirect clues. The first statement (S1) is open for preview.

Login with Google to unlock all statements.

How to study

This tab shows concrete study steps: what to underline in books, how to map current affairs, and how to prepare for similar questions.

Login with Google to unlock study guidance.

Micro-concepts

Discover the small, exam-centric ideas hidden in this question and where they appear in your books and notes.

Login with Google to unlock micro-concepts.

The Vault

Access hidden traps, elimination shortcuts, and Mains connections that give you an edge on every question.

Login with Google to unlock The Vault.

✓ Thank you! We'll review this.

SIMILAR QUESTIONS

CDS-I · 2003 · Q111 Relevance score: -5.13

Consider the following statements: I. All nematodes are parasitic in nature II. Earthworms are nocturnal animals III. Annelids have no true coelom. IV. The alimentary canal of flatworms has only one opening. Which of these statements is/are correct?

IAS · 2019 · Q28 Relevance score: -5.77

Consider the following statements : 1. Some species of turtles are herbivores. 2. Some species of fish are herbivores. 3. Some species of marine mammals are herbivores. 4. Some species of snakes are viviparous. Which of the statements given above are correct?

IAS · 2024 · Q18 Relevance score: -5.82

Consider the following : 1. Carabid beetles 2. Centipedes 3. Flies 4. Termites 5. Wasps Parasitoid species are found in how many of the above kind of organisms ?

CDS-I · 2005 · Q87 Relevance score: -6.97

From the evolutionary point of view which one among the following is the most primitive animal in comparison to the other three ?