GENERAL KNOWLEDGE

Detailed explanation-1: -fish, any of approximately 34, 000 species of vertebrate animals (phylum Chordata) found in the fresh and salt waters of the world. Living species range from the primitive jawless lampreys and hagfishes through the cartilaginous sharks, skates, and rays to the abundant and diverse bony fishes.

Detailed explanation-2: -Fish are considered vertebrates (with a backbone), and most fish have scales, fins, and gills. Fish use their gills to breathe, but some types of fish have lungs as well, and can breathe out of water for long periods of time.

Detailed explanation-3: -jawless fish, which include hagfish and lampreys. jawed vertebrates, which include: cartilaginous fish (sharks, rays, and ratfish) bony vertebrates, which include: ray-fins (the majority of living bony fish) lobe-fins, which include: coelacanths and lungfish.