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Chapter 13: Organisms & Populations

NCERT Solutions for CBSE Class 10 Biology — 24 solved questions with detailed explanations.

24

Questions

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Topics

Solved Questions

Q1. The interaction where both organisms benefit is called:

Parasitism
Commensalism
Mutualism
Competition

Difficulty: Easy · Topic: Interactions

Solution

Mutualism: both partners benefit (+/+). E.g., lichens, mycorrhiza, Rhizobium-legume.

Q2. Competition is:

no interaction
both benefit
one benefits
both organisms harmed (-/-)

Difficulty: Easy · Topic: Organisms & Populations

Solution

both organisms harmed (-/-).

Q3. Amensalism is:

one harmed, other unaffected (-/0)
both benefit
both harmed
one benefits

Difficulty: Easy · Topic: Organisms & Populations

Solution

one harmed, other unaffected (-/0).

Q4. Carrying capacity (K) is the:

minimum population
maximum population an environment can sustain
zero
average population

Difficulty: Easy · Topic: Organisms & Populations

Solution

maximum population an environment can sustain.

Q5. r-selected species have:

slow growth
many offspring, less parental care
long lifespan
few offspring, more care

Difficulty: Easy · Topic: Organisms & Populations

Solution

many offspring, less parental care.

Q6. Natality is:

death rate
emigration
birth rate
immigration

Difficulty: Easy · Topic: Organisms & Populations

Solution

birth rate.

Q7. Mortality is:

death rate
birth rate
immigration
emigration

Difficulty: Easy · Topic: Organisms & Populations

Solution

death rate.

Q8. Immigration is:

death
birth
movement into population
movement out

Difficulty: Easy · Topic: Organisms & Populations

Solution

movement into population.

Q9. Emigration is:

movement into
birth
movement out of population
death

Difficulty: Easy · Topic: Organisms & Populations

Solution

movement out of population.

Q10. Exponential growth: dN/dt =:

K-N
rN
rN(K-N)/K
rK

Difficulty: Easy · Topic: Organisms & Populations

Solution

rN.

Q11. In logistic growth, growth rate is maximum at:

N=K
N=K/2
N=2K
N=0

Difficulty: Easy · Topic: Organisms & Populations

Solution

N=K/2.

Q12. Predation is a:

mutalism
+/- interaction
0/0 interaction
+/+ interaction

Difficulty: Easy · Topic: Organisms & Populations

Solution

+/- interaction.

Q13. Brood parasitism is shown by:

sparrow
cuckoo (koel)
eagle
crow

Difficulty: Easy · Topic: Organisms & Populations

Solution

cuckoo (koel).

Q14. Batesian mimicry is when:

both same
neither
harmless species resembles harmful one
harmful resembles harmless

Difficulty: Easy · Topic: Organisms & Populations

Solution

harmless species resembles harmful one.

Q15. Mullerian mimicry is when:

harmless resembles harmful
neither
both harmless
two harmful species resemble each other

Difficulty: Easy · Topic: Organisms & Populations

Solution

two harmful species resemble each other.

Q16. The logistic growth model is represented by:

dN/dt = rN
dN/dt = rN(K-N)/K
dN/dt = K
dN/dt = rN²

Difficulty: Easy-Medium · Topic: Population Growth

Solution

Logistic (Verhulst-Pearl): dN/dt = rN(K-N)/K. N = population, r = intrinsic rate, K = carrying capacity.

Q17. Commensalism benefits:

both organisms
neither
one harms other
one organism, other unaffected (+/0)

Difficulty: Easy-Medium · Topic: Organisms & Populations

Solution

one organism, other unaffected (+/0).

Q18. Parasitism benefits:

one, other unaffected
one organism, harms other (+/-)
both
neither

Difficulty: Easy-Medium · Topic: Organisms & Populations

Solution

one organism, harms other (+/-).

Q19. K-selected species have:

fewer offspring, more parental care
rapid growth
short lifespan
many offspring

Difficulty: Easy-Medium · Topic: Organisms & Populations

Solution

fewer offspring, more parental care.

Q20. Biome with highest biodiversity is:

tundra
desert
tropical rainforest
taiga

Difficulty: Easy-Medium · Topic: Ecology

Solution

tropical rainforest.

Q21. Tundra is characterized by:

dense forests
permafrost and low temperatures
coral reefs
high rainfall

Difficulty: Easy-Medium · Topic: Ecology

Solution

permafrost and low temperatures.

Q22. Taiga (boreal forest) has mainly:

coniferous trees
cacti
deciduous trees
grasslands

Difficulty: Easy-Medium · Topic: Ecology

Solution

coniferous trees.

Q23. Savanna is a:

desert
tropical grassland with scattered trees
temperate forest
wetland

Difficulty: Easy-Medium · Topic: Ecology

Solution

tropical grassland with scattered trees.

Q24. Mangroves are found in:

mountains
coastal saline water
freshwater lakes
deserts

Difficulty: Easy-Medium · Topic: Ecology

Solution

coastal saline water.

Other Chapters in Biology

Ch 1: Reproduction in Organisms Ch 2: Sexual Reproduction in Plants Ch 3: Human Reproduction Ch 4: Reproductive Health Ch 5: Principles of Inheritance Ch 6: Molecular Basis of Inheritance Ch 7: Evolution Ch 8: Human Health & Disease Ch 9: Strategies for Enhancement Ch 10: Microbes in Human Welfare Ch 11: Biotechnology Principles Ch 12: Biotechnology Applications Ch 14: Ecosystem Ch 15: Biodiversity & Conservation Ch 16: Environmental Issues

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