Which of the following have species that can establish symbiotic relationship with other organisms? 1. Cnidarians 2. Fungi 3. Protozoa Select the correct answer using the code given below.
- A.1 and 2 only
- B.2 and 3 only
- C.1 and 3 only
- D.1, 2 and 3
Correct answer
Explanation
The correct answer is D, 1, 2 and 3. Cnidarians, fungi and protozoa all include species that live in close, mutually useful partnerships with other organisms.
Symbiosis means two different species living closely together, often to the benefit of both. Reef-building corals are cnidarians, and they host tiny algae called zooxanthellae in their tissues; the algae give the coral food by photosynthesis and its colour, and get shelter and nutrients in return. When stressed corals expel these algae, they turn white, which is coral bleaching. Among fungi, lichens are a partnership of a fungus with an alga or cyanobacterium, and mycorrhizae link fungi with plant roots to help them absorb water and phosphorus. Among protozoa, flagellates such as Trichonympha live in the gut of termites and digest the cellulose of wood for them.
A, B and C are wrong because each leaves out one group that clearly forms symbiotic relationships.
Exam tip: coral + zooxanthellae, fungus + alga (lichen), fungus + root (mycorrhiza), termite + gut protozoa.
Practice Questions
View allConsider the following statements :
I. Carbon dioxide (CO2) emissions in India are less than 0.5 t CO2/capita.
II. In terms of CO2 emissions from fuel combustion, India ranks second in Asia-Pacific region.
III. Electricity and heat producers are the largest sources of CO2 emissions in India.
Which of the statements given above is/are correct?
- A.I and III only
- B.II only
- C.II and III only
- D.I, II and III
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India is the second-largest emitter of fuel-combustion CO2 in the Asia-Pacific after China, and power and heat generation is its biggest source, but its per capita emissions are well above 0.5 tonne.
Read the full explanation →The term 'Domestic Content Requirement' is sometimes seen in the news with reference to
- A.Developing solar power production in our country
- B.Granting licences to foreign T.V. channels in our country
- C.Exporting our food products to other countries
- D.Permitting foreign educational institutions to set up their campuses in our country
Show answer
Domestic Content Requirement (DCR) is the rule that certain solar projects must use solar cells and modules made in India.
Read the full explanation →In the context of which of the following do some scientists suggest the use of cirrus cloud thinning technique and the injection of sulphate aerosol into stratosphere?
- A.Creating the artificial rains in some regions
- B.Reducing the frequency and intensity of tropical cyclones
- C.Reducing the adverse effects of solar wind on the Earth
- D.Reducing the global warming
Show answer
Both ideas are geoengineering proposals meant to cool the planet by changing how much heat enters or leaves the Earth.
Read the full explanation →Regarding Peacock tarantula (Gooty tarantula), consider the following statements :
I. It is an omnivorous crustacean.
II. Its natural habitat in India is only limited to some forest areas.
III. In its natural habitat, it is an arboreal species.
Which of the statements given above is/are correct?
- A.I only
- B.I and II
- C.II only
- D.II and III
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The Gooty tarantula is a tree-dwelling spider found only in a few forest patches of India; it is not a crustacean.
Read the full explanation →Consider the following pairs :
Terms sometimes seen in the news — Their origin
1. Annex-I Countries — Cartagena Protocol
2. Certified Emissions Reductions — Nagoya Protocol
3. Clean Development Mechanism — Kyoto Protocol
Which of the pairs given above is/are correctly matched?
- A.1 and 2 only
- B.2 and 3 only
- C.3 only
- D.1, 2 and 3
Show answer
All three terms come from the climate treaties, the UNFCCC and its Kyoto Protocol, so only the third pair is right.
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