NEET Topic-wise & A
Topic 1: ECOSYSTEM – STRUCTURE & FUNCTION
NEET: Previous Years Questions
01. The term ecosystem was coined by
(1) E. Haeckel
(2) E. Warming
(3) E.P. Odum
(4) A. G. Tansley (NEET-I 2016)
✅ (4) A. G. Tansley
02. Which one of the following is a characteristic feature of cropland ecosystem?
(1) Absence of weeds
(2) Ecological succession
(3) Absence of soil organisms
(4) Least genetic diversity (NEET-I 2016)
✅ (4) Least genetic diversity
Model Questions
03. Functional unit of nature is
(1) Habitat
(2) Ecosystem
(3) Community
(4) Biome
✅ (2) Ecosystem
04. Vertical distribution of different species occupying different levels is called
(1) Stratification
(2) Fragmentation
(3) Ecozones
(4) Zonation
✅ (1) Stratification
05. Which of the following is the 4 basic components of functioning of an ecosystem?
(1) Productivity, Stratification, Respiration, Nutrient cycling
(2) Producers, Consumers, Decomposers, Energy flow
(3) Productivity, Decomposition, Energy flow, Nutrient cycling
(4) Producers, Consumers, Decomposers, Trophic levels
✅ (3) Productivity, Decomposition, Energy flow, Nutrient cycling
06. Which of the following is not true about pond ecosystem?
(1) A pond is a shallow, simple, self-sustainable water body.
(2) Pond does not exhibit all basic components of an ecosystem.
(3) Autotrophic components of a pond include Phytoplankton, some algae and the floating, submerged and marginal plants.
(4) In a pond ecosystem, Fungi, bacteria and flagellates act as Decomposers.
✅ (2) Pond does not exhibit all basic components of an ecosystem.
Topic 2: PRODUCTIVITY
NEET: Previous Years Questions
07. In an ecosystem, if the Net Primary Productivity (NPP) of first trophic level is 100 x (kcal m-2) yr-1, what would be the GPP (Gross Primary Productivity) of the third trophic level of the same ecosystem?
(1) x⁄10 (kcal m−2 yr−1)
(2) x (kcal m−2 yr−1)
(3) 10x (kcal m−2 yr−1)
(4) 100x⁄3x (kcal m−2 yr−1)
✅ (2) x (kcal m−2 yr−1)
08. In the equation GPP - R = NPP
GPP is Gross Primary Productivity
NPP is Net Primary Productivity
R here is ________.
(1) Respiratory quotient
(2) Respiratory loss
(3) Reproductive allocation
(4) Photosynthetically active radiation (NEET 2023)
✅ (2) Respiratory loss
09. In the equation GPP R = NPP, R represents:
(1) Radiant energy
(2) Retardation factor
(3) Environment factor
(4) Respiration losses (NEET 2021)
✅ (4) Respiration losses
10. In relation to Gross primary productivity and Net primary productivity of an ecosystem, which one of the following statements is correct?
(1) Gross primary productivity is always less than Net primary productivity.
(2) Gross primary productivity is always more than Net primary productivity.
(3) Gross primary productivity and Net primary productivity are one and same.
(4) There is no relationship between Gross primary productivity and Net primary productivity. (NEET 2020)
✅ (2) Gross primary productivity is always more than Net primary productivity.
Model Questions
11. Which ecosystem has maximum biomass?
(1) Grass land ecosystem
(2) Pond ecosystem
(3) Lake ecosystem
(4) Forest ecosystem
✅ (4) Forest ecosystem
12. Which of the following relations is correct regarding GPP and NPP of an ecosystem?
(1) NPP = R – GPP
(2) NPP = GPP – R
(3) GPP = NPP – R
(4) GPP = R – NPP
✅ (2) NPP = GPP – R
13. The rate of formation of new organic matter by consumers is called
(1) Net primary productivity (NPP)
(2) Gross primary productivity (GPP)
(3) Secondary productivity
(4) Respiration loss (R)
✅ (3) Secondary productivity
14. The gross primary productivity of an ecosystem is 160 tons of organic matter. Its 25% is used in respiration. Calculate NPP.
(1) 120 tons
(2) 40 tons
(3) 110 tons
(4) 200 tons
✅ (1) 120 tons
15. Primary productivity varies in different ecosystems because it depends on
(1) Environmental factors
(2) Availability of nutrients
(3) Photosynthetic capacity of plants
(4) All the above
✅ (4) All the above
16. Which of the following statements about productivity is wrong?
(1) Primary productivity of almost all ecosystems is a constant.
(2) Annual net primary productivity of whole biosphere is about 170 billion tons (dry weight) of organic matter.
(3) Net primary productivity (NPP) is the available biomass for the consumption to heterotrophs.
(4) The rate of biomass production (productivity) is expressed in g–2 yr–1 or (kcal m–2) yr–1.
✅ (1) Primary productivity of almost all ecosystems is a constant.
Topic 3: DECOMPOSITION
NEET: Previous Years Questions
17. Identify the correct statements:
A. Detrivores perform fragmentation.
B. The humus is further degraded by some microbes during mineralization.
C. Water soluble inorganic nutrients go down into the soil and get precipitated by a process called leaching.
D. The detritus food chain begins with living organisms.
E. Earthworms break down detritus into smaller particles by a process called catabolism.
Choose the correct answer from the options given below:
(1) B, C, D only
(2) C, D, E only
(3) D, E, A only
(4) A, B, C only (NEET 2023)
✅ (4) A, B, C only
Model Questions
18. The breakdown of detritus into smaller particles by detritivores is called
(1) Leaching
(2) Humification
(3) Mineralization
(4) Fragmentation
✅ (4) Fragmentation
19. The set of processes which occur simultaneously is
(1) Fragmentation, Leaching, Catabolism
(2) Fragmentation, Humification, Mineralization
(3) Catabolism, Humification, Mineralization
(4) Leaching, catabolism, Humification
✅ (1) Fragmentation, Leaching, Catabolism
20. Which of the following processes during decomposition is correctly described?
(1) Catabolism: Last step in the decomposition under fully anaerobic condition.
(2) Leaching: Water soluble inorganic nutrients rise to the top layers of soil.
(3) Fragmentation: Carried out by organisms such as earthworm.
(4) Humification: Leads to the accumulation of a dark-coloured substance humus which undergoes microbial action at a very fast rate.
✅ (3) Fragmentation: Carried out by organisms such as earthworm.
21. In a particular climatic condition, decomposition rate is slower if
(1) Detritus is rich in nitrogen, sugars & lignin
(2) Detritus is rich in lignin & chitin
(3) Detritus is rich in chitin, nitrogen & sugars
(4) Detritus is rich in nitrogen & humus
✅ (2) Detritus is rich in lignin & chitin
22. Regarding climatic factors that influence decomposition, select the correct statement.
(1) Cool and moist environment favour decomposition.
(2) Warm and moist environment inhibit decomposition.
(3) Low temperature & anaerobiosis inhibit decomposition.
(4) High temperature & anaerobiosis inhibit decomposition.
✅ (3) Low temperature & anaerobiosis inhibit decomposition.
Topic 4: ENERGY FLOW
NEET: Previous Years Questions
23. The primary producers of the deep-sea hydrothermal vent ecosystem are
(1) green algae
(2) chemosynthetic bacteria
(3) blue-green algae
(4) coral reefs (NEET-II 2016)
✅ (2) chemosynthetic bacteria
Model Questions
24. Plants capture .............. of the photosynthetically active radiation (PAR).
(1) 2 – 10%
(2) 10 – 20%
(3) 15 – 25%
(4) 5 – 15%
✅ (1) 2 – 10%
25. The predator food chain is also called
(1) Parasitic food chain
(2) Detritus food chain
(3) Auxiliary food chain
(4) Grazing food chain
✅ (4) Grazing food chain
26. The flow of energy in the ecosystem is
(1) Bidirectional
(2) Cyclic
(3) Unidirectional
(4) Multidirectional
✅ (3) Unidirectional
27. Select the true statements from the following.
(1) In an aquatic ecosystem, GFC is the major conduit for energy flow.
(2) DFC may be connected with GFC at some levels.
(3) Some organisms of DFC are prey to the GFC animals.
(4) Measuring biomass in fresh weight is more accurate because it is the exact mass of body which remains constant.
✅ (4) Measuring biomass in fresh weight is more accurate because it is the exact mass of body which remains constant.
28. Identify the likely organisms 1, 2, 3 and 4 in the food web shown below:
(1) 1- Deer, 2- Rabbit, 3- Frog, 4- Rat
(2) 1- Dog, 2- Squirrel, 3- Bat, 4- Deer
(3) 1- Rat, 2- Dog, 3- Tortoise, 4- Crow
(4) 1- Deer, 2- Rabbit, 3- Rat, 4- Pigeon
✅ (1) 1- Deer, 2- Rabbit, 3- Frog, 4- Rat
29. A specific place of organisms in the food chain is known as
(1) Food web
(2) Trophic level
(3) GFC
(4) DFC
✅ (2) Trophic level
30. Which one of the following animals may occupy more than one trophic levels in the same ecosystem at the same time?
(1) Sparrow
(2) Goat
(3) Lion
(4) Frog
✅ (1) Sparrow
31. The amount of energy is
(1) Increased at successive trophic levels.
(2) Constant at all trophic levels.
(3) Decreased at trophic levels up to 2nd consumer.
(4) Decreased at successive trophic levels.
✅ (4) Decreased at successive trophic levels.
32. The amount of living material in a trophic level at a given time is called
(1) Biomass
(2) Standing crop
(3) Dead biomass
(4) Dry weight
✅ (2) Standing crop
33. The loss of energy as one proceeds from one trophic level to the next higher level is approximately
(1) 30%
(2) 40%
(3) 60%
(4) 90%
✅ (4) 90%
34. If 30 J of energy is trapped at producer level, then how much energy will be available to peacock as food in the following chain?
Plant → Mice → Snake → Peacock
(1) 0.3 J
(2) 0.03 J
(3) 0.003 J
(4) 0.0003 J
✅ (2) 0.03 J
Topic 5: ECOLOGICAL PYRAMIDS
NEET: Previous Years Questions
35. Which of the following statements is not correct?
(1) Pyramid of biomass in sea is generally inverted.
(2) Pyramid of biomass in sea is generally upright.
(3) Pyramid of energy is always upright.
(4) Pyramid of numbers in a grassland ecosystem is upright. (NEET 2021)
✅ (2) Pyramid of biomass in sea is generally upright.
36. Match the trophic levels with their correct species examples in grassland ecosystem.
Select the correct option:
(a) (b) (c) (d)
(1) (iv) (iii) (ii) (i)
(2) (i) (ii) (iii) (iv)
(3) (ii) (iii) (iv) (i)
(4) (iii) (ii) (i) (iv) (NEET 2020)
✅ (3) (ii) (iii) (iv) (i)
37. Which of the following ecological pyramids is generally inverted?
(1) Pyramid of biomass in a sea
(2) Pyramid of numbers in grassland
(3) Pyramid of energy
(4) Pyramid of biomass in a forest (NEET 2019)
✅ (1) Pyramid of biomass in a sea
38. What type of ecological pyramid would be obtained with the following data?
Secondary consumer: 120 g
Primary consumer: 60 g
Primary producer: 10 g
(1) Inverted pyramid of biomass
(2) Pyramid of energy
(3) Upright pyramid of numbers
(4) Upright pyramid of biomass (NEET 2018)
✅ (1) Inverted pyramid of biomass
39. Which ecosystem has the maximum biomass?
(1) Grassland ecosystem
(2) Pond ecosystem
(3) Lake ecosystem
(4) Forest ecosystem (NEET 2017)
✅ (4) Forest ecosystem
Model Questions
40. Which one of the following statements for the pyramid of energy is incorrect?
(1) Its base is broad.
(2) It shows energy content of different trophic level organisms.
(3) It is sometimes inverted in shape.
(4) When energy flows from a trophic level to next, some energy is always lost as heat.
✅ (3) It is sometimes inverted in shape.
41. An inverted pyramid of number and an inverted pyramid of biomass are respectively seen in
(1) Grass land and tree ecosystem
(2) Sea and tree ecosystem
(3) Tree and sea ecosystem
(4) Sea and grass land ecosystem
✅ (3) Tree and sea ecosystem
42. Primary producers convert only .......... of the energy in the sunlight available to them into NPP.
(1) 1%
(2) 5%
(3) 10%
(4) 15%
✅ (1) 1%
43. Select the false statement from the following.
(1) A trophic level represents a functional level, not a species as such.
(2) A species may occupy more than one trophic level in the same ecosystem at the same time.
(3) In most ecosystems, all pyramids are upright.
(4) Energy at a lower trophic level is always less than at a higher level.
✅ (4) Energy at a lower trophic level is always less than at a higher level.
44. Which of the following statements is wrong regarding an ecological pyramid
(1) Insects feeding on a big tree is an example for inverted pyramids.
(2) It considers the same species belonging to two or more trophic levels.
(3) It does not include saprophytes (decomposers).
(4) In inverted pyramid of biomass, small standing crop of phytoplankton supports large standing crop of zooplankton.
✅ (2) It considers the same species belonging to two or more trophic levels.
45. Given below is an imaginary pyramid of numbers. What could be one of the possibilities about certain organisms at some of the different levels?
(1) Level PC is insects and level SC is small insectivorous birds.
(2) Level PP is phytoplankton in sea and whale on top level TC.
(3) Level one PP is pipal trees and the level SC is sheep.
(4) Level PC is rats and level SC is cats.
✅ (1) Level PC is insects and level SC is small insectivorous birds.
46. Pyramid of energy is always upright, because
(1) When energy flows, each trophic level gets equal amount of energy.
(2) When energy flows, higher trophic levels get more energy.
(3) When energy flows from a trophic level to the next, some energy is always lost as heat.
(4) When energy flows from a trophic level to the next, producers release more energy.
✅ (3) When energy flows from a trophic level to the next, some energy is always lost as heat.
Topic 6: ECOLOGICAL SUCCESSION
NEET: Previous Years Questions
47. Which of the following would appear as the pioneer organisms on bare rocks?
(1) Mosses
(2) Green algae
(3) Lichens
(4) Liverworts (NEET-I 2016)
✅ (3) Lichens
Model Questions
48. A gradual, slow and predictable change in the species composition of an area leading to a climax community is called
(1) Primary succession
(2) Secondary succession
(3) Ecological succession
(4) Xerarch succession
✅ (3) Ecological succession
49. The entire sequences of communities that successively change in an area are called
(1) Sere
(2) Trophic level
(3) Hydrarch
(4) Xerarch
✅ (1) Sere
50. Select the false statement
(1) In succession, individual transitional communities are termed seral stages or seral communities.
(2) The species invading a bare area are called pioneer species.
(3) Succession and evolution were parallel processes.
(4) During succession, there is a change in species diversity, decrease in number of species and organisms and a decrease in total biomass.
✅ (4) During succession, there is a change in species diversity, decrease in number of species and organisms and a decrease in total biomass.
51. The succession taking place on newly cooled lava, bare rock, newly created pond or reservoir etc. are examples for
(1) Hydrarch succession
(2) Primary succession
(3) Secondary succession
(4) Xerarch succession
✅ (2) Primary succession
52. Assertion: Primary succession is a very slow process.
Reason: To establish a biotic community, fertile soil must be formed.
(1) Assertion and reason are true and reason is the correct explanation of assertion.
(2) Assertion and reason are true but reason is not the correct explanation of assertion.
(3) Assertion is true but reason is wrong.
(4) Both assertion and reason are wrong.
✅ (1) Assertion and reason are true and reason is the correct explanation of assertion.
53. Regarding secondary succession, odd one out.
(1) Abandoned farm lands
(2) Newly created pond
(3) Burned or cut forests
(4) Lands that are flooded
✅ (2) Newly created pond
54. Pick out the wrong statement from the following.
(1) Secondary succession takes place in an area after the existed organisms are lost.
(2) Natural or human induced disturbances (deforestation, fire etc.) convert a particular seral stage to an earlier stage.
(3) Hydrarch succession progresses from mesic to hydric conditions.
(4) The species invading a bare area are called pioneer species.
✅ (3) Hydrarch succession progresses from mesic to hydric conditions.
55. The pioneer species in xerarch and hydrarch succession are respectively
(1) Lichens and sedges
(2) Phytoplankton and sedges
(3) Lichens and zooplanktons
(4) Lichens and phytoplankton
✅ (4) Lichens and phytoplankton
56. The correct sequence of seral stages in hydrosere is
(1) Phytoplankton → rooted-submerged plants → rooted-floating angiosperms → free-floating plants → reed-swamp → marsh-meadow → scrub → trees
(2) Phytoplankton → rooted-floating angiosperms → rooted-submerged plants → free-floating plants → marsh-meadow → reed-swamp → scrub → trees
(3) Phytoplankton → rooted-submerged plants → free-floating plants → rooted-floating angiosperms → scrub → reed-swamp → marsh-meadow → trees
(4) Phytoplankton → rooted-floating angiosperms → rooted-submerged plants → free-floating plants → marsh-meadow → scrub → reed-swamp → trees
✅ (1) Phytoplankton → rooted-submerged plants → rooted-floating angiosperms → free-floating plants → reed-swamp → marsh-meadow → scrub → trees
57. In primary succession on rocks (xerophytic habitat), the seral stage next to the lichens is generally
(1) Gymnosperms
(2) Bryophytes
(3) Bushes
(4) Grasses
✅ (2) Bryophytes
Topic 7: NUTRIENT CYCLING
NEET: Previous Years Questions
58. The amount of nutrients, such as carbon, nitrogen, phosphorus and calcium present in the soil at any given time, is referred as:
(1) Climax
(2) Climax community
(3) Standing state
(4) Standing crop (NEET 2021)
✅ (3) Standing state
Model Questions
59. Which of the following belongs to sedimentary cycle?
(1) Sulphur cycle & Phosphorus cycle
(2) Sulphur cycle & Carbon cycle
(3) Nitrogen cycle & Carbon cycle
(4) Carbon cycle & Phosphorous cycle
✅ (1) Sulphur cycle & Phosphorus cycle
60. For the sedimentary type of biogeochemical cycles, the reservoir is
(1) Atmosphere
(2) Earth’s crust
(3) Water
(4) Living organisms
✅ (2) Earth’s crust
61. Select the wrong statement
(1) Environmental factors such as soil, moisture, pH, temperature, etc. regulate the rate of release of nutrients into the atmosphere.
(2) In carbon cycle, atmospheric input is comparatively lower than that of phosphorous cycle.
(3) 49% of dry weight organisms is carbon.
(4) A major amount of carbon returns to the atmosphere as CO2 through respiration.
✅ (2) In carbon cycle, atmospheric input is comparatively lower than that of phosphorous cycle.
62. The amount of carbon fixed annually in the biosphere through photosynthesis is about
(1) 1.4×1012 kg
(2) 1.4×1013 kg
(3) 4×1012 kg
(4) 4×1013 kg
✅ (4) 4×1013 kg
63. The major natural reservoir of phosphorus is
(1) Rock
(2) Soil
(3) Water
(4) Air
✅ (1) Rock
64. Given below is the schematic representation of phosphorous cycle. Label A, B, C and D.
(1) A= Rock minerals, B= Decomposition, C= Weathering, D= Detritus
(2) A= Detritus, B= Absorption, C= Weathering, D= Dead organisms
(3) A= Rock minerals, B= Weathering, C= Decomposition, D= Detritus
(4) A= Detritus, B= Decomposition, C= Weathering, D= Rock minerals
✅ (4) A= Detritus, B= Decomposition, C= Weathering, D= Rock minerals
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