Assertion (A): The two kingdom classification system proposed by Linnaeus was eventually found to be inadequate.
Reason (R): It did not distinguish between eukaryotes and prokaryotes, unicellular and multicellular organisms, or photosynthetic and non-photosynthetic organisms.
The two-kingdom classification was inadequate because it failed to distinguish between prokaryotes and eukaryotes, unicellular and multicellular organisms, and autotrophs and heterotrophs.
Question 202 of 300
📘 CLASS XI
Assertion (A): In earlier classification systems, Chlamydomonas and Spirogyra were placed together under algae.
Reason (R): They were grouped together because all the organisms included in that specific kingdom had a cell wall.
Earlier systems grouped organisms mainly on the presence of a cell wall without considering cellular organisation.
Question 203 of 300
📘 CLASS XI
Assertion (A): The three-domain system of classification results in a total of six kingdoms.
Reason (R): The three-domain system divides the Kingdom Protista into two separate domains.
The three-domain system divides Kingdom Monera into Archaea and Bacteria, not Kingdom Protista.
Question 204 of 300
📘 CLASS XI
Assertion (A): Fungi and green plants were separated into different kingdoms in Whittaker's classification.
Reason (R): Fungi possess a cell wall made of chitin, whereas green plants possess a cellulosic cell wall.
Differences in cell wall composition and nutrition justify placing fungi and plants in separate kingdoms.
Question 205 of 300
📘 CLASS XI
Assertion (A): Bacteria as a group show the most extensive metabolic diversity.
Reason (R): All bacteria are autotrophic and synthesize their own food from inorganic substrates.
Bacteria exhibit enormous metabolic diversity because they include both autotrophic and heterotrophic forms.
Question 206 of 300
📘 CLASS XI
Assertion (A): Archaebacteria can survive in extreme conditions like hot springs and extreme salty areas.
Reason (R): Archaebacteria possess a different cell wall structure from other bacteria.
Their unique cell wall composition enables archaebacteria to survive in extreme environments.
Question 207 of 300
📘 CLASS XI
Assertion (A): Methanogens are responsible for the production of methane (biogas) from animal dung.
Reason (R): Methanogens naturally reside in the gut of several ruminant animals such as cows and buffaloes.
Methanogens present in the digestive tract of ruminants produce methane, which continues to be generated from dung.
Question 208 of 300
📘 CLASS XI
Assertion (A): Cyanobacteria often form blooms in polluted water bodies.
Reason (R): Cyanobacteria are chemosynthetic autotrophs.
Cyanobacteria are photosynthetic autotrophs containing chlorophyll a.
Question 209 of 300
📘 CLASS XI
Assertion (A): Chemosynthetic autotrophic bacteria play a great role in recycling nutrients like nitrogen, phosphorus, iron and sulphur.
Reason (R): They oxidise inorganic substances such as nitrates, nitrites and ammonia and use the released energy for ATP production.
Chemosynthetic bacteria recycle nutrients by oxidising inorganic compounds and obtaining energy from them.
Question 210 of 300
📘 CLASS XI
Assertion (A): Heterotrophic bacteria are the most abundant in nature and mostly act as decomposers.
Reason (R): Heterotrophic bacteria are responsible for causing diseases such as cholera, typhoid and tetanus.
Both statements are true. Heterotrophic bacteria are the most abundant bacteria in nature, and the majority act as decomposers. Some heterotrophic bacteria are also pathogenic and cause diseases such as cholera, typhoid and tetanus. However, pathogenicity does not explain why heterotrophic bacteria are abundant or why they mainly function as decomposers. Therefore, Reason is true but is not the correct explanation of the Assertion.
