ANAND CLASSES Study Material and Notes provide top Assertion and Reason (A&R) questions on types of heterotrophic nutrition for Class 10 Science Biology. Perfect for quick revision and practice to understand saprotrophic, parasitic, and holozoic nutrition.
Assertion and Reason Based Questions With Answers and Explanation
Q1.
Assertion (A): Holozoic nutrition involves the ingestion, digestion, absorption, assimilation, and egestion of food.
Reason (R): In holozoic nutrition, organisms secrete digestive enzymes outside their body to break down food before absorption.
Answer: (C) Assertion is correct, but Reason is incorrect.
Explanation: Holozoic nutrition involves consuming solid or liquid food, which is then digested inside the body through specialized digestive organs. However, the second statement describes extracellular digestion, which is characteristic of saprotrophic organisms, not holozoic ones.
Q2.
Assertion (A): Saprotrophic organisms secrete digestive enzymes onto dead organic matter to break it down into simpler substances.
Reason (R): Saprotrophic organisms, like fungi and bacteria, directly ingest complex food particles into their bodies for digestion.
Answer: (C) Assertion is correct, but Reason is incorrect.
Explanation: Saprotrophic organisms decompose dead organic matter by secreting enzymes outside their bodies, breaking down complex substances into simpler forms that can be absorbed. They do not ingest food particles directly like holozoic organisms.
Q3.
Assertion (A): Parasitic nutrition is a type of heterotrophic nutrition where an organism derives nutrients from a living host.
Reason (R): In parasitic nutrition, the host always benefits from the relationship.
Answer: (C) Assertion is correct, but Reason is incorrect.
Explanation: Parasites harm their host by depriving them of nutrients, causing weakness or disease. The host does not benefit from this relationship; rather, it suffers due to the parasite’s presence.
Q4.
Assertion (A): Heterotrophic nutrition includes saprotrophic, parasitic, and holozoic modes of nutrition.
Reason (R): Heterotrophic organisms cannot synthesize their own food and depend on other organisms for nourishment.
Answer: (A) Both Assertion and Reason are correct, and Reason is the correct explanation of Assertion.
Explanation: Heterotrophic organisms obtain their food from other sources, as they lack the ability to produce their own food like autotrophs. The different types of heterotrophic nutrition include holozoic, saprotrophic, and parasitic nutrition.
Q5.
Assertion (A): All saprotrophs are decomposers, but not all decomposers are saprotrophs.
Reason (R): Decomposers include both saprotrophs and detritivores, which help in breaking down organic matter.
Answer: (A) Both Assertion and Reason are correct, and Reason is the correct explanation of Assertion.
Explanation: Saprotrophs, like fungi and bacteria, secrete enzymes to decompose dead matter externally, while detritivores, like earthworms, physically break down organic material. Both contribute to decomposition, but saprotrophs alone do not encompass all decomposers.
Q6.
Assertion (A): In parasitic nutrition, the parasite derives its nutrition at the expense of the host.
Reason (R): Parasitic nutrition is always beneficial to the host, as the host receives necessary nutrients from the parasite.
Answer: (D) Assertion is correct, but Reason is incorrect.
Explanation: In parasitic nutrition, the parasite derives its nutrients from a host, often harming the host in the process. The relationship is harmful to the host, not beneficial.
Q7.
Assertion (A): Holozoic nutrition involves the complete digestion and assimilation of food within the digestive system.
Reason (R): In holozoic nutrition, the organisms secrete digestive enzymes outside their bodies to break down food before absorption.
Answer: (B) Assertion is correct, but Reason is incorrect.
Explanation: In holozoic nutrition, food is ingested and digested internally within specialized organs, not externally like saprotrophic nutrition. The statement about external digestion applies to saprotrophic organisms, not holozoic ones.
Q8.
Assertion (A): Holozoic organisms take in solid or liquid food, break it down inside the body, and absorb the nutrients.
Reason (R): The breakdown of food in holozoic organisms is completely extracellular, occurring outside the body.
Answer: (C) Assertion is correct, but Reason is incorrect.
Explanation: In holozoic nutrition, digestion occurs inside the body, not outside. The food is broken down inside specialized digestive organs, such as the stomach and intestines.
Q9.
Assertion (A): Saprotrophs play an important role in ecosystems by decomposing dead organic material.
Reason (R): Saprotrophs feed on living organisms and parasitize them for nourishment.
Answer: (D) Assertion is correct, but Reason is incorrect.
Explanation: Saprotrophs, like fungi and certain bacteria, break down dead organic material. They do not parasitize living organisms. The parasitic mode of nutrition is distinct from saprotrophic nutrition.
Q10.
Assertion (A): All animals exhibit holozoic nutrition.
Reason (R): Holozoic nutrition is found in organisms that ingest solid or liquid food, digest it internally, and absorb the nutrients.
Answer: (B) Assertion is incorrect, but Reason is correct.
Explanation: While many animals exhibit holozoic nutrition, not all animals follow this mode. For example, some parasitic organisms like tapeworms may follow parasitic nutrition instead.
Q11.
Assertion (A): Fungi are examples of saprotrophic organisms.
Reason (R): Saprotrophs like fungi secrete enzymes onto decaying matter to break it down and absorb the nutrients.
Answer: (A) Both Assertion and Reason are correct, and Reason is the correct explanation of Assertion.
Explanation: Fungi, such as molds and mushrooms, are saprotrophic organisms that decompose organic material by secreting digestive enzymes externally, breaking down complex substances into absorbable nutrients.
Q12.
Assertion (A): Parasitic nutrition involves a relationship between two organisms, where one benefits at the expense of the other.
Reason (R): Parasites can only survive by consuming the food resources of their hosts without causing harm.
Answer: (D) Assertion is correct, but Reason is incorrect.
Explanation: In parasitic nutrition, the parasite derives nutrients from its host, often harming it in the process. The host does not benefit and often experiences negative effects, such as disease or malnutrition.
Q13.
Assertion (A): Holozoic organisms use specialized digestive systems for internal digestion.
Reason (R): Holozoic nutrition involves digesting food outside the body and then absorbing the nutrients.
Answer: (B) Assertion is correct, but Reason is incorrect.
Explanation: In holozoic nutrition, organisms ingest food, which is then digested internally in the digestive system. The food is not broken down outside the body like in saprotrophic organisms.
Q14.
Assertion (A): Saprotrophs are crucial for nutrient cycling in ecosystems.
Reason (R): Saprotrophic organisms secrete digestive enzymes to break down organic matter externally, recycling nutrients back into the soil.
Answer: (A) Both Assertion and Reason are correct, and Reason is the correct explanation of Assertion.
Explanation: Saprotrophic organisms, such as fungi and bacteria, break down dead organic matter externally by secreting enzymes, returning important nutrients to the soil and enabling nutrient cycling in ecosystems.
Q15.
Assertion (A): In parasitic nutrition, the host always suffers due to the feeding habits of the parasite.
Reason (R): Parasitic organisms depend on the host for nourishment, often weakening or damaging the host.
Answer: (A) Both Assertion and Reason are correct, and Reason is the correct explanation of Assertion.
Explanation: Parasitic organisms obtain nutrients from the host, causing harm to the host in the process. The host typically experiences negative effects, such as illness or nutrient deprivation.
Q16.
Assertion (A): Holozoic nutrition is a form of ingestion where organisms consume solid or liquid food and digest it internally.
Reason (R): Holozoic nutrition is characterized by external digestion of food particles, similar to saprotrophic nutrition.
Answer: (C) Assertion is correct, but Reason is incorrect.
Explanation: In holozoic nutrition, digestion occurs internally, not externally as described in the Reason. Organisms that exhibit holozoic nutrition ingest food and break it down within their digestive systems.
Q17.
Assertion (A): Parasitic nutrition is a type of nutrition where one organism benefits while the other is harmed.
Reason (R): In parasitic nutrition, the parasite absorbs nutrients from the host, but the relationship benefits both organisms.
Answer: (D) Assertion is correct, but Reason is incorrect.
Explanation: Parasitic nutrition involves one organism benefiting (the parasite) at the expense of the other (the host), which is harmed in the process. The host does not benefit in this relationship.
Q18.
Assertion (A): All fungi exhibit saprotrophic nutrition.
Reason (R): Fungi secrete enzymes onto organic material and absorb the nutrients after decomposition.
Answer: (A) Both Assertion and Reason are correct, and Reason is the correct explanation of Assertion.
Explanation: Fungi are classic examples of saprotrophic organisms, as they decompose dead organic material by secreting digestive enzymes and absorbing the resulting nutrients.
Q19.
Assertion (A): Holozoic nutrition is exclusive to animals.
Reason (R): Holozoic nutrition is only seen in organisms that consume food, digest it internally, and absorb nutrients through a digestive tract.
Answer: (B) Assertion is incorrect, but Reason is correct.
Explanation: While many animals exhibit holozoic nutrition, some protists and fungi (e.g., slime molds) also follow similar nutritional modes. Therefore, it is not exclusive to animals.
Q20.
Assertion (A): Parasitic nutrition involves the consumption of living organisms, usually at their expense.
Reason (R): Parasites often cause harm to their hosts by draining essential nutrients, which may lead to the host’s weakening or death.
Answer: (A) Both Assertion and Reason are correct, and Reason is the correct explanation of Assertion.
Explanation: In parasitic nutrition, the parasite lives off the host organism, causing damage by absorbing nutrients, often resulting in harm to the host, such as disease or nutrient depletion.
Q21.
Assertion (A): Fungi and bacteria are examples of saprotrophic organisms.
Reason (R): Saprotrophic organisms decompose dead organic matter and recycle nutrients back into the environment.
Answer: (A) Both Assertion and Reason are correct, and Reason is the correct explanation of Assertion.
Explanation: Both fungi and bacteria are saprotrophic organisms that break down dead organic material, contributing to the recycling of nutrients in ecosystems.
Q22.
Assertion (A): Holozoic organisms digest food in a specialized internal digestive system.
Reason (R): Holozoic nutrition is characterized by the absorption of pre-digested food particles from the surrounding environment.
Answer: (C) Assertion is correct, but Reason is incorrect.
Explanation: In holozoic nutrition, food is ingested, digested internally within a specialized digestive system, and then absorbed. It is not absorbed as pre-digested particles from the environment, which is a characteristic of saprotrophic organisms.
Q23.
Assertion (A): Saprotrophic nutrition helps in the decomposition of dead organic matter.
Reason (R): Saprotrophs ingest organic matter directly through their bodies for digestion.
Answer: (D) Assertion is correct, but Reason is incorrect.
Explanation: Saprotrophic organisms decompose dead organic matter by secreting enzymes externally, not by ingesting it directly. They break down complex organic material outside their bodies before absorbing the nutrients.
Q24.
Assertion (A): In parasitic nutrition, the parasite benefits while the host is harmed.
Reason (R): Parasitic organisms always kill their hosts after obtaining nutrients from them.
Answer: (C) Assertion is correct, but Reason is incorrect.
Explanation: While parasitic organisms benefit from the relationship by obtaining nutrients from their hosts, they do not always kill the host. Some parasites live in a way that does not immediately result in the host’s death, but they still cause harm.
Q25.
Assertion (A): Holozoic nutrition is found in both plants and animals.
Reason (R): Holozoic organisms ingest food and digest it internally for nutrient absorption.
Answer: (B) Assertion is incorrect, but Reason is correct.
Explanation: While animals typically exhibit holozoic nutrition, plants do not. Plants are autotrophs, which synthesize their own food through photosynthesis and do not ingest food.
Q26.
Assertion (A): Holozoic nutrition involves the ingestion and internal digestion of food, which is absorbed by the organism.
Reason (R): Holozoic organisms secrete digestive enzymes outside their bodies to break down food before absorption.
Answer: (D) Assertion is correct, but Reason is incorrect.
Explanation: In holozoic nutrition, food is ingested and digested internally in specialized organs like the stomach and intestines, not externally as in saprotrophic organisms.
Q27.
Assertion (A): Parasitic organisms usually weaken their hosts by depriving them of essential nutrients.
Reason (R): The host benefits from the relationship as the parasite provides essential nutrients in return.
Answer: (D) Assertion is correct, but Reason is incorrect.
Explanation: Parasitic organisms harm their hosts by depriving them of nutrients. The host does not benefit from this relationship; instead, it experiences negative effects like malnutrition or disease.
Q28.
Assertion (A): All fungi exhibit parasitic nutrition.
Reason (R): Fungi are able to live on living organisms, obtaining nutrients at their expense.
Answer: (B) Assertion is incorrect, but Reason is correct.
Explanation: Not all fungi are parasitic. Many fungi are saprotrophic and obtain nutrients from decomposing dead organic matter. Only certain fungi, like some species of rusts and smuts, exhibit parasitic nutrition.
Q29.
Assertion (A): In saprotrophic nutrition, organisms break down organic matter externally and absorb the resulting nutrients.
Reason (R): Saprotrophic organisms do not rely on living organisms for nutrition but feed on dead and decaying organic matter.
Answer: (A) Both Assertion and Reason are correct, and Reason is the correct explanation of Assertion.
Explanation: Saprotrophic organisms, such as fungi and bacteria, decompose dead organic material by secreting digestive enzymes outside their bodies and absorbing the resulting nutrients. They do not depend on living hosts for nutrition.
Q30.
Assertion (A): In parasitic nutrition, the parasite always kills the host after consuming its nutrients.
Reason (R): In parasitic relationships, the parasite absorbs nutrients from its host, often weakening or killing it over time.
Answer: (C) Assertion is incorrect, but Reason is correct.
Explanation: While parasitic organisms weaken or harm the host by extracting nutrients, they do not always kill the host immediately. Some parasites live in the host for extended periods without killing them right away.
Q31.
Assertion (A): Saprotrophs are important decomposers in ecosystems.
Reason (R): Saprotrophs digest organic material outside their bodies, helping recycle nutrients back into the environment.
Answer: (A) Both Assertion and Reason are correct, and Reason is the correct explanation of Assertion.
Explanation: Saprotrophs, such as fungi and bacteria, break down organic material externally through enzyme secretion, contributing significantly to nutrient recycling in ecosystems.
Q32.
Assertion (A): Holozoic organisms digest food in their stomachs and intestines.
Reason (R): Holozoic nutrition involves ingestion, digestion, absorption, and assimilation of food inside the body.
Answer: (A) Both Assertion and Reason are correct, and Reason is the correct explanation of Assertion.
Explanation: Holozoic organisms digest food inside their bodies in specialized organs such as the stomach and intestines, where the nutrients are absorbed and assimilated for energy and growth.
Q33.
Assertion (A): In parasitic nutrition, the host suffers from the feeding behavior of the parasite.
Reason (R): The host provides nourishment to the parasite without any harm to itself.
Answer: (D) Assertion is correct, but Reason is incorrect.
Explanation: In parasitic nutrition, the parasite feeds on the host and typically harms it by depriving it of essential nutrients. The relationship is detrimental to the host, not beneficial.
Q34.
Assertion (A): Saprotrophic organisms secrete enzymes to break down complex organic substances.
Reason (R): Saprotrophs absorb the nutrients after decomposing organic matter outside their bodies.
Answer: (A) Both Assertion and Reason are correct, and Reason is the correct explanation of Assertion.
Explanation: Saprotrophic organisms, such as fungi and certain bacteria, secrete digestive enzymes onto dead organic matter to break it down into simpler substances that they can absorb.
Q35.
Assertion (A): Parasitic nutrition is an example of a symbiotic relationship where both organisms benefit.
Reason (R): In parasitic nutrition, one organism benefits at the expense of the other, typically harming the host.
Answer: (D) Assertion is incorrect, but Reason is correct.
Explanation: Parasitic nutrition is not a symbiotic relationship in which both organisms benefit. In fact, it harms the host, as the parasite takes nutrients at the host’s expense.
Q36.
Assertion (A): Holozoic organisms consume solid or liquid food, which is digested in specialized digestive systems.
Reason (R): Holozoic nutrition involves external digestion and absorption of nutrients.
Answer: (C) Assertion is correct, but Reason is incorrect.
Explanation: Holozoic nutrition involves ingestion and internal digestion of food within the digestive system, not external digestion like saprotrophic organisms.
Q37.
Assertion (A): Saprotrophic nutrition is carried out by organisms like fungi and bacteria.
Reason (R): These organisms break down organic matter by ingesting it directly through their bodies.
Answer: (D) Assertion is correct, but Reason is incorrect.
Explanation: Saprotrophic organisms like fungi and bacteria secrete enzymes outside their bodies to break down organic material before absorbing the nutrients. They do not ingest it directly as suggested in the Reason.
Q38.
Assertion (A): Parasitic nutrition involves a relationship where the parasite derives nourishment from its host.
Reason (R): In parasitic nutrition, the host benefits by receiving essential nutrients from the parasite.
Answer: (D) Assertion is correct, but Reason is incorrect.
Explanation: In parasitic nutrition, the parasite benefits at the expense of the host. The host is usually harmed by nutrient deprivation or other negative effects.
Q39.
Assertion (A): Holozoic nutrition is a characteristic of many animals, including humans.
Reason (R): Holozoic organisms absorb food after it has been broken down externally by digestive enzymes.
Answer: (C) Assertion is correct, but Reason is incorrect.
Explanation: Holozoic nutrition involves the internal digestion of food, not external digestion. In humans and other animals, food is ingested, digested internally, and then absorbed.
Q40.
Assertion (A): In parasitic nutrition, parasites may not necessarily kill their hosts immediately.
Reason (R): Some parasites can live in a host for extended periods without causing harm.
Answer: (A) Both Assertion and Reason are correct, and Reason is the correct explanation of Assertion.
Explanation: Some parasites can live inside their hosts for long periods without immediately killing them. They rely on the host for nutrients over time, often weakening it rather than causing immediate death.
Q41.
Assertion (A): Saprotrophic organisms play a vital role in the decomposition process.
Reason (R): These organisms digest dead organic material and return essential nutrients to the soil.
Answer: (A) Both Assertion and Reason are correct, and Reason is the correct explanation of Assertion.
Explanation: Saprotrophs, like fungi and bacteria, break down dead organic material, recycling nutrients back into the ecosystem, which supports plant growth and other forms of life.
Q42.
Assertion (A): All parasitic organisms have a harmful effect on their hosts.
Reason (R): In parasitic relationships, the parasite typically benefits, and the host suffers from nutrient loss and possible damage.
Answer: (A) Both Assertion and Reason are correct, and Reason is the correct explanation of Assertion.
Explanation: Parasitic organisms always benefit by feeding on their hosts, and this often causes harm to the host in the form of nutrient depletion, illness, or even death.
Q43.
Assertion (A): Holozoic organisms ingest food, digest it internally, and absorb the nutrients.
Reason (R): Holozoic nutrition is dependent on the secretion of digestive enzymes outside the body for breaking down food.
Answer: (C) Assertion is correct, but Reason is incorrect.
Explanation: Holozoic nutrition involves internal digestion within the digestive system, not external digestion as in saprotrophic nutrition. The food is ingested, digested inside the body, and the nutrients are absorbed.
Q44.
Assertion (A): In parasitic nutrition, the parasite derives nourishment from the host.
Reason (R): Parasitic organisms always help their hosts by providing essential nutrients.
Answer: (D) Assertion is correct, but Reason is incorrect.
Explanation: In parasitic nutrition, the parasite feeds on the host, often harming it by depriving it of essential nutrients. The relationship is not beneficial to the host.
Q45.
Assertion (A): Saprotrophic nutrition helps in the recycling of nutrients in ecosystems.
Reason (R): Saprotrophs feed on living organisms to derive nutrition, benefiting both themselves and the host.
Answer: (D) Assertion is correct, but Reason is incorrect.
Explanation: Saprotrophs feed on dead organic material, not living organisms, and help recycle nutrients by decomposing it. This process does not involve benefiting the host but rather decomposing organic matter for nutrient cycling.
Q46.
Assertion (A): Holozoic organisms include most animals and humans.
Reason (R): Holozoic organisms digest food inside their bodies after ingesting it.
Answer: (A) Both Assertion and Reason are correct, and Reason is the correct explanation of Assertion.
Explanation: Holozoic organisms, including humans, ingest food, digest it internally, and absorb nutrients through their digestive system, which is characteristic of holozoic nutrition.
Q47.
Assertion (A): Parasitic nutrition involves one organism benefiting at the expense of another.
Reason (R): The host organism in parasitic relationships often suffers due to nutrient deprivation and other harmful effects.
Answer: (A) Both Assertion and Reason are correct, and Reason is the correct explanation of Assertion.
Explanation: Parasitic organisms obtain their nourishment from a host, often causing harm such as nutrient loss, disease, or damage to the host. The host does not benefit from this relationship.
Q48.
Assertion (A): Fungi and bacteria are examples of organisms that exhibit saprotrophic nutrition.
Reason (R): These organisms secrete digestive enzymes to break down organic material outside their bodies and absorb the resulting nutrients.
Answer: (A) Both Assertion and Reason are correct, and Reason is the correct explanation of Assertion.
Explanation: Fungi and bacteria are saprotrophic organisms that secrete digestive enzymes externally to break down organic material, then absorb the nutrients for growth and reproduction.
Q49.
Assertion (A): Parasitic nutrition is a form of symbiotic relationship where one organism benefits and the other is harmed.
Reason (R): Parasitic nutrition always results in the host’s death after the parasite has absorbed all the nutrients.
Answer: (C) Assertion is correct, but Reason is incorrect.
Explanation: While parasitic nutrition is harmful to the host, it does not always result in the host’s immediate death. Some parasites live inside their host for extended periods, weakening it rather than causing death right away.
Q50.
Assertion (A): Saprotrophs are essential decomposers in ecosystems.
Reason (R): They break down complex organic materials into simpler substances, which are then recycled back into the ecosystem.
Answer: (A) Both Assertion and Reason are correct, and Reason is the correct explanation of Assertion.
Explanation: Saprotrophs, like fungi and bacteria, play a crucial role in decomposing organic matter, returning nutrients to the soil and supporting the cycling of elements in ecosystems.
Q51.
Assertion (A): In parasitic nutrition, the parasite benefits by absorbing nutrients from the host.
Reason (R): The host gains nourishment and benefits from the relationship with the parasite.
Answer: (D) Assertion is correct, but Reason is incorrect.
Explanation: In parasitic nutrition, the parasite benefits by taking nutrients from the host. The relationship is harmful to the host, which often suffers from nutrient depletion, illness, or even death.
Q52.
Assertion (A): All fungi exhibit saprotrophic nutrition.
Reason (R): Fungi secrete digestive enzymes outside their bodies to break down organic matter and absorb the nutrients.
Answer: (B) Assertion is incorrect, but Reason is correct.
Explanation: While many fungi exhibit saprotrophic nutrition, not all fungi follow this mode. Some fungi, such as parasitic fungi, may obtain nutrients from living hosts rather than decomposing dead organic material.
Q53.
Assertion (A): Holozoic nutrition involves ingestion, internal digestion, and absorption of nutrients.
Reason (R): Holozoic organisms secrete enzymes outside their bodies to break down food before absorbing it.
Answer: (C) Assertion is correct, but Reason is incorrect.
Explanation: In holozoic nutrition, digestion occurs internally, not externally like in saprotrophic organisms. The food is ingested and digested inside the body before nutrients are absorbed.
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