The question asks to identify which option is NOT a characteristic of Chlorophyceae (green algae). We need to recall the defining features of Chlorophyceae and compare them with the given options.
Correct Option: B) Fucoxanthin as accessory pigment
The question asks about the specific type of asexual reproduction that occurs in most brown algae. To answer this, one needs to recall the characteristic features of asexual spores in brown algae (Phaeophyceae).
C) Biflagellate pear-shaped zoospores. Most brown algae reproduce asexually by means of zoospores. These zoospores are characteristically pear-shaped (pyriform) and possess two laterally inserted flagella of unequal length (heterokont flagella), making them biflagellate.
The question asks about the contribution of algae to the total carbon dioxide fixation on Earth. This is a factual question related to ecology and photosynthesis, specifically the role of aquatic organisms in global carbon cycling.
Correct Option: A) Half. Algae, particularly phytoplankton in the oceans, are estimated to perform about half of the total photosynthetic CO2 fixation on Earth. This makes them crucial primary producers in aquatic ecosystems and significant contributors to the global carbon cycle.
The question asks why Bryophytes are called 'amphibians of the plant kingdom'. This analogy refers to their unique dependency on both land and water for their life cycle, similar to how amphibians (animals) live on land but return to water for reproduction.
C) They live in soil but depend on water for sexual reproduction. This option correctly identifies the reason for the analogy. Bryophytes are terrestrial plants that require water for the movement of male gametes to the female gametes, making water essential for their sexual reproduction, much like amphibians need water for breeding.
The question asks about the dominant phase in the life cycle of bryophytes. To answer this, we need to understand the alternation of generations in bryophytes and identify which generation is more prominent, long-lived, and independent.
Correct Option: A) Gametophyte — In bryophytes, the gametophyte is the dominant, independent, and photosynthetic phase of the life cycle. The sporophyte is dependent on the gametophyte.
The question asks to identify the nature of gemmae in liverworts. This requires knowledge of the reproductive strategies of liverworts, specifically their asexual reproduction methods.
D) Green multicellular asexual buds in gemma cups
This option accurately describes gemmae. They are indeed green, multicellular structures that function as asexual buds and are found within gemma cups on the thallus of liverworts like Marchantia. They detach and grow into new plants, representing a form of asexual reproduction.