9.Global warming is a serious problem on Earth nowadays. It is the increase in the average temperature of the earth's atmosphere.
10.Fishes are water animals. A fish usually has tails and paired fins on its back and on its belly that enable it to swim. Scales are thin but tough sheets arranged all over their bodies. Fishes also have gills. The gills are found in slits near the head of the fish behind its mouth. Gills let the fish breathe in water.
