Exams › NEET › Biology › Organisms and Populations
98 questions with worked solutions.
Q1. In India, human population is heavily weighted towards the younger age groups as a result of
Answer: short life span of many individuals and high birth rate
A population becomes youth-heavy when births are high, adding many children to the base of the age structure. If life span is short, fewer people remain in older age groups, so the younger groups make up a larger share.
Q2. Association of animals when both partners are benefitted
Answer: mutualism
Mutualism is the type of association in which both animals benefit from the relationship. The other options describe different interactions: commensalism benefits one without affecting the other, and amensalism harms one while the other is unaffected.
Q3. Competition for light, nutrients and space is most severe between
Answer: closely related organisms growing in the same area/niche
Closely related organisms usually have very similar requirements for light, nutrients, and space, so they overlap heavily in what they use. When they live in the same niche or area, that overlap makes competition most intense.
Q4. A mutually beneficial association necessary for survival of both partners is
Answer: mutualism/symbiosis
Mutualism is a symbiotic relationship in which both partners benefit, and in some cases the association is essential for survival of both. Commensalism benefits one organism while the other is unaffected, and amensalism harms one without helping the other.
Answer: Symbiosis when the interaction is useful to both the populations
The correct choice is the one describing a relationship that benefits both populations; that is the usual meaning of symbiosis in this context. The other options confuse symbiosis with commensalism or with no-effect interactions.
Q6. It is much easier for a small animal to run uphill than for a large animal, because
Answer: smaller animals have a higher metabolic rate.
Smaller animals generally have a higher metabolic rate per unit body mass, so they can supply energy more rapidly for strenuous activity like running uphill. This makes uphill locomotion easier for them than for larger animals.
Q7. Animals/organisms floating on the surface of water are
Answer: plankton
Plankton are organisms that drift with water currents and are commonly found near the surface where light and food are available. The other choices refer to different habitat zones or bottom-dwelling life.
Q8. In desert grasslands which type of animals are relatively more abundant?
Answer: Fossorial
Desert grasslands are hot and dry, so animals that live underground are better protected from extreme temperatures and water loss. Fossorial animals are therefore relatively more abundant than arboreal, aquatic, or purely diurnal ones.
Q9. Association between Sucker Fish (Remora) and Shark is
Answer: Commensalism
Remora fish attach to sharks to get transportation, protection, and leftover food. The shark is generally unaffected, which makes this relationship commensalism.
Q10. Annual migration does not occur in the case of
Answer: Salamander
Annual migration is a predictable seasonal movement between regions, common in birds like the Siberian crane and Arctic tern, and in fish like salmon. Salamanders generally do not make such annual long-distance migrations, so they are the exception.
Q11. Penguin occurs in
Answer: Antarctica
Penguins are adapted to cold southern habitats, and many species live in and around Antarctica. While some penguins are found elsewhere in the Southern Hemisphere, Antarctica is the best answer here.
Q12. In terrestrial habitats, temperature and rainfall conditions are influenced by:
Answer: water transformations
Water transformations (evaporation, condensation, freezing, melting) strongly influence temperature and rainfall by moving heat and moisture through the atmosphere. These phase changes drive weather patterns, unlike the other options which are plant or biological processes.
Answer: Poison fangs in snakes
Poison fangs in snakes are primarily an offensive adaptation used to subdue prey, not an innate escape mechanism from predation. The other options are classic anti-predator defenses such as camouflage, inflation, or concealment.
Q14. Two different species can not live for long duration in the same niche or habitat. This law is
Answer: Gause's hypothesis
Gause's hypothesis, also called the competitive exclusion principle, says two species cannot stably occupy the same niche for long because one will outcompete the other. The other options refer to unrelated biological laws or theories.
Q15. Which one of the following is categorised as a parasite in true sense?
Answer: Head louse living on the human scalp as well as laying eggs on human hair
The head louse is a classic ectoparasite: it lives on the human scalp, feeds on the host, and completes its life cycle there. The other options describe blood-feeding, temporary dependence, or brood parasitism, which are not the same as a true parasite in this sense.
Q16. The long-term prospects for a truly human civilization depend in a large measure on
Answer: the ability of humanity to moderate its fecundity
The passage points to population growth as the central long-term challenge. A truly sustainable human civilization depends largely on limiting birth rates so population does not outstrip resources and social capacity.
Q17. Most animals are tree dwellers in a:
Answer: Tropical rain forest
Tropical rain forests have dense vegetation and a multi-layered canopy, providing ample niches for arboreal (tree-dwelling) animals to thrive.
Q18. Benthic organisms are affected most by
Answer: Sediment characteristics of aquatic ecosystems
Benthic organisms live at the bottom of aquatic ecosystems and are directly influenced by the sediment characteristics, such as texture, composition, and organic matter content, which determine their habitat and food availability.
Q19. Large woody vines are more commonly found in:
Answer: tropical rainforests
Large woody vines, also known as lianas, are most commonly found in tropical rainforests due to the dense vegetation and competition for sunlight, which encourages their growth as they climb trees to reach light.
Q20. The logistic population growth is expressed by the equation:
Answer: (b) dN/dt = rN (K - N / K)
The logistic population growth equation is given by dN/dt = rN (K - N / K), where r is the intrinsic growth rate, N is the population size, and K is the carrying capacity. This equation accounts for environmental resistance as the population approaches carrying capacity.