Fishes survive in water mainly because they possess
The correct answer is: D
Explanation
Gills are specialized respiratory organs found in fish that allow them to extract oxygen from water. While a streamlined body, scales, and paired fins are all essential adaptations for fish to navigate and survive in water, none of them directly relate to the process of oxygen extraction and respiration like gills do. However, without gills, fish would not be able to respire efficiently underwater and would not survive in their aquatic habitats.