Phacus belongs to:

Correct option is D

Correct Answer: (d) Euglenophyta
Explanation:
→ Phacus is a genus of euglenoids (Euglenophyta) — unicellular flagellates, often photosynthetic, with characteristic leaf-shaped cells.
→ Found in freshwater habitats, important in plankton communities.
Information Booster:
→ Euglenophytes exhibit mixotrophy (photosynthesis + phagotrophy) under varying light/nutrient conditions.
Additional Information (Other Options):
(a) Diatoms: silicified algae (different group).
(b) Blue-green algae: cyanobacteria (prokaryotes).
(c) Zooplankton: animals/protozoa that are heterotrophic (Phacus is autotrophic/mixotrophic protist).