NEET MCQs Practice on Biological Classification Class-XI Biology, Free unlimited practice on Biological Classification Class-XI Biology Mcqs

Question 211 of 300

📘 CLASS XI

Assertion (A): Under unfavourable conditions, bacteria produce spores to survive.

Reason (R): Bacteria reproduce exclusively by sexual reproduction.

Bacteria produce spores under unfavourable conditions for survival. They reproduce mainly by binary fission, not exclusively by sexual reproduction.

Question 212 of 300

📘 CLASS XI

Assertion (A): Mycoplasma organisms can survive without oxygen.

Reason (R): Mycoplasma are the largest living cells known to science.

Mycoplasma can survive without oxygen but they are the smallest living cells, not the largest.

Question 213 of 300

📘 CLASS XI

Assertion (A): The boundaries of Kingdom Protista are considered not well defined.

Reason (R): What one biologist considers a photosynthetic protistan may be considered a plant by another biologist.

Protista has ill-defined boundaries because photosynthetic protists may be regarded as plants by some biologists.

Question 214 of 300

📘 CLASS XI

Assertion (A): Kingdom Protista acts as a link dealing with plants, animals, and fungi.

Reason (R): All members of Kingdom Protista are strictly terrestrial.

Protista links plants, animals and fungi, but its members are primarily aquatic rather than terrestrial.

Question 215 of 300

📘 CLASS XI

Assertion (A): Diatoms have left behind large amounts of cell wall deposits in their habitats, known as diatomaceous earth.

Reason (R): The cell walls of diatoms are embedded with silica, making them indestructible.

The silica-embedded indestructible walls of diatoms accumulate over billions of years to form diatomaceous earth.

Question 216 of 300

📘 CLASS XI

Assertion (A): Diatomaceous earth is widely used in polishing and the filtration of oils and syrups.

Reason (R): Diatoms are the chief producers in the oceans.

Diatomaceous earth is used because it is gritty due to silica deposits, not because diatoms are chief producers.

Question 217 of 300

📘 CLASS XI

Assertion (A): Red tides can kill marine animals such as fishes.

Reason (R): Red dinoflagellates undergo rapid multiplication and release toxins into the water.

Rapid multiplication of toxin-producing dinoflagellates causes red tides that kill marine animals.

Question 218 of 300

📘 CLASS XI

Assertion (A): Euglenoids exhibit mixotrophic nutrition, meaning they can be autotrophic or heterotrophic.

Reason (R): They are photosynthetic in sunlight but behave like heterotrophs by predating on smaller organisms when deprived of sunlight.

This dual mode of nutrition defines the mixotrophic nature of euglenoids.

Question 219 of 300

📘 CLASS XI

Assertion (A): The pigments of euglenoids are identical to those present in higher plants.

Reason (R): Euglenoids are primarily found in marine environments.

Euglenoids possess pigments similar to higher plants but are mostly freshwater organisms.

Question 220 of 300

📘 CLASS XI

Assertion (A): Slime moulds form an aggregation called a plasmodium under favourable conditions.

Reason (R): During unfavourable conditions, the plasmodium differentiates and forms fruiting bodies bearing spores.

The reason describes the next stage of the life cycle and does not explain plasmodium formation.

Biological-Classification MCQs