Brown hydra is:A. Hydra vulgarisB. Hydra viridisC. Hydra fuscaD. Hydra gangeticus

The correct answer is C. Hydra fusca.
1. What is Hydra?
o Hydra is a genus of small, freshwater organisms belonging to the phylum Cnidaria and class Hydrozoa. These organisms are known for their simple body structure and remarkable regenerative abilities.
2. Brown Hydra (Hydra fusca):
o Hydra fusca is commonly referred to as the Brown Hydra because of its characteristic brown color.
o The brown color is due to the presence of symbiotic algae or pigments in its body tissues, which help it in photosynthesis and provide additional nutrition.
3. Why Not the Other Options?
o A. Hydra vulgaris: Known as the common Hydra, Hydra vulgaris is typically pale or translucent in color and does not have the brown pigmentation.
o B. Hydra viridis: Known as the Green Hydra, Hydra viridis contains symbiotic green algae (Chlorella), giving it a green color rather than brown.
o D. Hydra gangeticus: A lesser-known species of Hydra, but it is not commonly referred to as the Brown Hydra.
The Brown Hydra is scientifically known as Hydra fusca, making C. Hydra fusca the correct answer.