Fish are specially adapted so that they can breathe under the water. They have special organs called gills. Gills are bars of tissue at each side of the fish's head. They carry masses of finger-like projections that contain tiny blood vessels. The fish gulp in water through their mouths and pass it out through the gills. The gills are rich in blood, and they extract oxygen from the water and pass it into the fish's blood. In this way the gills have the same function as the lungs of air-breathing animals. But these gills would not work without the aid of water.
FACT FILE
Most of a fish's body is composed of powerful muscles and its internal organs are squeezed into a tiny area. The fins are used to propel and stabilize the fish in the water.
resources: Tell me why (Chancellor Press)
image 1: https://www.anglersatlas.com/media/photos/5a961788e8c9c.jpg:700
image 2: http://www.mm.rsu.edu.sd/en/images/sampledata/parks/shapeimage_2.png
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