Assertion & Reason Test: Organisms & Populations - NEET MCQ

The human population represents the logistic growth curve as the numbers of human beings are increasing rapidly but available resources are not increasing at the same pace. Such a growth pattern is not sustainable because at one point the human population would reach a place where there would not be enough resources for everyone.

Topic in NCERT: Logistic growth

Line in NCERT: "No population of any species in nature has at its disposal unlimited resources to permit exponential growth. This leads to competition between individuals for limited resources."

Correct answer is D. Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

• Natality rate, also known as the birth rate, represents the number of births in a population over a specific period.
• Natality indeed increases the number of individuals in a population by contributing new individuals through births.
• When natality rate is high, it leads to an increase in the population size, as more individuals are being added through births.
• The increase in population size, in turn, affects population density, which is the number of individuals per unit area.
• Therefore, both the population size and population density increase when the natality rate is high.

Topic in NCERT: Natality

Line in NCERT: "Natality refers to the number of births during a given period in the population that are added to the initial density."

Ecology includes six levels of organization that are organism, population, community, ecosystem, biosphere and biome.

Topic in NCERT: Ecology

Line in NCERT: "Ecology is basically concerned with four levels of biological organisation - organisms, populations, communities and biomes."

Population is a group of people therefore it's attributes are different from an individual organism.

Topic in NCERT: Population Attributes

Line in NCERT: "A population has certain attributes whereas, an individual organism does not."

Clown fish maintain a commensalistic relation with the sea anemone. In this interaction, one species benefits and the other is neither harmed nor benefited. Sea anemone has stinging tentacles that provide protection to Clown fish from predators. The sea anemone does not appear to derive any benefit from the clownfish.

Topic in NCERT: Commensalism

Line in NCERT: "Another example of commensalism is the interaction between sea anemone that has stinging tentacles and the clown fish that lives among them. The fish gets protection from predators which stay away from the stinging tentacles. The anemone does not appear to derive any benefit by hosting the clown fish."

• The Assertion is correct because it accurately describes brood parasitism as a reproductive strategy among certain bird species.
• The Reason is also correct; it explains that the similarity in egg appearance reduces the chances of host birds detecting and ejecting the foreign eggs.
• Since the Reason explains why the Assertion is true, we conclude that both the Assertion and Reason are true, and the Reason is the correct explanation of the Assertion.

- The assertion is correct; plants do have a range of chemical defenses aimed at deterring herbivores, which can include toxic compounds and substances that inhibit feeding.

- The reason is false; while some chemical compounds can attract pollinators, the primary purpose of many plant chemicals is indeed to protect against herbivores, not to attract them.

- Therefore, the reason does not correctly explain the assertion, making Option B the right choice.

• Assertion Analysis: The assertion is true. Organisms that breed multiple times can adapt better to environmental changes because they have more opportunities to reproduce and pass on advantageous traits.
• Reason Analysis: The reason is false. While some organisms that reproduce once may have high reproductive success, this does not universally apply to all species, especially given the variability of environmental pressures.
• Explanation: Therefore, while both statements are true, the reason does not correctly explain the assertion, as the success of breeding multiple times is context-dependent and can enhance adaptability rather than diminish it.