Aquatic and Marine Biology

Butterfly, breast (breaststroke), and freestyle are competitive swimming strokes. Diving is a completely separate aquatic sport involving acrobatic entries into water from a platform or springboard, not a swimming stroke.

Spirogyra thrives in stagnant freshwater bodies like ponds, ditches, and slow-moving streams where it can form floating green mats. It cannot survive in saltwater conditions and requires calm, nutrient-rich freshwater for its filamentous growth.

Female frogs release eggs during spawning when physically stimulated by the male's clasp during amplexus. This tactile stimulation triggers ovulation and egg release. Water currents and male vocalizations may attract frogs but do not directly induce spawning. Female-female stimulation does not occur in natural mating behavior.

Aquatic larvae like tadpoles excrete ammonia because they live in water and can easily dilute this toxic waste product. Ammonia requires large amounts of water for elimination, making it suitable only for aquatic animals. Reptiles, birds, and adult amphibians excrete uric acid or urea, which require less water.

The green color of Green Hydra comes from symbiotic Zoochlorella algae (Chlorella) living within the endodermal cells of the hydra. This is an example of mutualism where the algae provide food through photosynthesis and receive protection. The color is not due to pigments in epidermis, endodermis, or mesoglea.

Gambusia eats larvae and eggs of mosquitoes and keeps the water clean.

This is the correct option. Pomfret is a seawater fish. It is found in the Atlantic, Indian and Pacific Oceans.

Ichthyophis is a genus of caecilian amphibians - legless, burrowing amphibians that resemble earthworms or snakes. Despite their snake-like appearance, they are amphibians (Class Amphibia, Order Gymnophiona). They are not reptiles, fish, birds, or mammals.

Frog eggs are mesolecithal - they contain a moderate amount of yolk that is unevenly distributed (more at the vegetal pole). Alecithal eggs have no yolk (e.g., placental mammals), macrolecithal have abundant yolk (birds, reptiles), and telolecithal is a synonym for macrolecithal. The moderate yolk in frog eggs supports tadpole development.

Turtles are reptiles belonging to the order Testudines, characterized by their protective shells. Salamanders and newts are amphibians, while toads and frogs are also amphibians. Reptiles are cold-blooded vertebrates with scales, while amphibians typically have moist skin and undergo metamorphosis.

London Zoo opened the first public aquarium in 1853, making it the first zoo to display marine life to the public. The aquarium was housed within the London Zoo's Regent's Park location and showcased marine species that had never before been seen by the general public. The Vancouver Public Aquarium opened in 1956, while Stuttgart Zoo and New York Aquarium were established later in the 20th century.

 ‘Pisciculture’ is the science of rearing fish.

Phytoplankton are microscopic marine plants that drift near ocean surfaces and form the base of aquatic food chains. Through photosynthesis, they produce about 50% of Earth's oxygen and support marine ecosystems.

Ducks have webbed feet that are specially adapted for swimming. The webbing between their toes acts like a paddle, increasing surface area and pushing more water with each stroke. Eagles and parrots have talons for perishing and gripping, while crossbills have specialized beaks for opening seeds.

Pinctada is the genus of pearl oysters that are commercially cultured in India for pearl production. These marine bivalve molluscs deposit layers of nacre around foreign particles, forming pearls. The other options are incorrect: Heliotis (abalone), Anodonta (freshwater mussel), and Mytilus (marine mussel) are not used for pearl culture.