Which of the following pairs is of unicellular algae?
Answer: (B) Chlorella and Spirulina. Answer: (B) Chlorella and Spirulina.
- A.Anabaena and Volvox
- B.Chlorella and Spirulina✓
- C.Laminaria and Sargassum
- D.Gelidium and Gracilaria
Correct Answer
(B) Chlorella and Spirulina
Solution & Explanation
Answer: (B) Chlorella and Spirulina. Solution: Per the official 2020 key, Chlorella is a unicellular alga rich in proteins used as a food supplement; Spirulina is also treated as unicellular in this item. The other pairs are multicellular: Laminaria and Sargassum are brown algae, and Gelidium and Gracilaria are red algae (both with multicellular thalli), while Anabaena/Volvox is a wrong pair (Volvox is colonial, not unicellular). Note: Spirulina is strictly a cyanobacterium (Monera), not a true alga, making this a controversial item, but the answer follows the official external key. NCERT Reference: Class XI Biology, Plant Kingdom, p.26, lines 14-15 — "Chlorella, a unicellular alga rich in proteins, is used as food supplement even by space travellers."