Aquatic and Marine Biology

The Gangetic river dolphin (Platanista gangetica) was declared India's national aquatic animal in 2009 to raise awareness about its conservation. It's a critically endangered freshwater dolphin species found in the Ganges and Brahmaputra river systems.

Octopuses have three hearts - two branchial hearts pump blood through the gills, and one systemic heart circulates blood to the rest of the body. This is unique among animals.

The River Dolphin (specifically the Gangetic dolphin, Platanista gangetica) was declared India's national aquatic animal in 2009 to raise conservation awareness. They are endangered freshwater dolphins found in the Ganges and Brahmaputra river systems. The other options are either wrong animal types or not designated as national symbols.

This is a duplicate of question 46874 with identical content and options. The River Dolphin (Gangetic dolphin, Platanista gangetica) was declared India's national aquatic animal in 2009. They are endangered freshwater dolphins found in the Ganges and Brahmaputra river systems.

The Gangetic River Dolphin was declared India's national aquatic animal in 2009 to raise awareness about conservation efforts for this endangered species. Found primarily in the Ganges and Brahmaputra river systems, it represents India's freshwater biodiversity.

Sharks have skeletons made entirely of cartilage, not bone. Cartilage is a flexible, lightweight tissue that provides structural support while allowing greater maneuverability than bone. All other options - teeth, gills, and liver - are body parts that sharks do possess.

Sailfish are recognized as the fastest fish in the ocean, capable of bursts up to 110 km/h (68 mph). They have large sail-like dorsal fins and streamlined bodies built for incredible speed. While marlin and swordfish are also fast swimmers (marlin can reach 80 km/h, swordfish 97 km/h), sailfish hold the official record. The option 'Great blue shar' appears to be a typo for 'Great blue shark,' which is not among the fastest swimmers.

Caviar is processed salted roe (eggs) of sturgeon and other fish species. It's considered a luxury food item. The eggs are carefully harvested and cured. Jams, insect larvae, and chicken feet are unrelated to caviar.

Sharks are most likely to mistake surfers for sea turtles due to the silhouette similarity when paddling - both appear as oval shapes with limbs (surfboard arms, turtle flippers). Sharks don't typically mistake humans for other sharks, beluga whales (Arctic species), or intentionally target humans.

Sharks have specialized sensory organs called ampullae of Lorenzini located in their snout (rostrum). These gel-filled pores detect weak electrical fields generated by muscle contractions in prey, allowing sharks to locate even hidden or buried animals. The snout houses these electroreceptors, not the teeth, dorsal fin, or eyes.

Most shark attacks are cases of mistaken identity, where the shark confuses a human for its natural prey like seals or sea lions. This explains why many attacks are 'hit-and-run' - the shark bites, realizes the human isn't its usual prey, and releases. Sharks don't typically stalk humans for hours, nor are they selective about morning versus evening attacks.

Great white sharks are selective predators that typically investigate potential prey before committing to an attack. They often approach cautiously, bump, or bite试探ally to determine if something is food. This picky behavior conserves energy and reduces risk of injury. They are not indiscriminate attackers nor do they attack primarily for dominance displays.

Bull sharks are known for their aggressive, unpredictable attack patterns and are responsible for many near-shore attacks. They can survive in freshwater and often hunt in murky shallow waters where human encounters are more likely. While tiger sharks can also attack humans, the question singles out bull sharks as having the characteristic attack behavior referenced in the context.

Bull sharks are widely considered the most dangerous shark species due to their aggressive nature, tendency to inhabit shallow coastal waters and freshwater rivers where humans frequently swim, and having one of the highest documented attack rates. While great white and tiger sharks are also dangerous, bull sharks' proximity to human populations makes them particularly hazardous.

Saltwater crocodiles are the largest living reptiles, reaching lengths up to 7 meters and weights over 1,000 kg. Green anacondas are large snakes but generally smaller than saltwater crocodiles. King cobras are venomous but much smaller, while tuataras are relatively small reptiles endemic to New Zealand.