What is External fertilization?

• A. Fertilization that occurs inside the body of an organism
• B. Fertilization that occurs outside the body of an organism. The sperms and eggs are released in an external environment. Usually requires a body of water
• C. Fertilization that occurs within the nucleus of a cell
• D. A type of fertilization seen only in plants

Answer: (B)

External fertilization occurs when the fusion of egg and sperm happens outside the bodies of the parents. Gametes are released into the surrounding environment—often into water—where they meet and fertilization occurs. This strategy is common in many aquatic animals like fish and amphibians and relies on releasing large numbers of gametes to increase the chance of a successful encounter, though it comes with risks from water conditions and predation. It contrasts with internal fertilization, where fertilization happens inside the female reproductive tract, and it isn’t a plant-specific process.