Explain/ describe the mechanism of locomotion in finned fish/ How does locomotion occurs in finned fish/ explain/ describe the adaptation of fish to locomotion in its habitat/ water.

-It has streamlined; body to reduce resistance to enable it move easily through water;
-It has inflexible head; which enables fish to maintain forward thrust;
-It has scales; that overlap and point backwards to reduce friction/ resistance during movement and prevent wetting of the skin;
-It secretes mucus; which covers the body and reduces friction during movement;
-It has flexible backbone with muscle blocks (called myotomes); which contract and relax to bring about side to side (undulating) movement;
-It has lateral line system along the length of the body; for sensitivity (i.e. enable it detect vibrations and changes of pressure in water) enabling it to respond suitably;
-It has a swim bladder; which provides it with buoyancy; and enable it to adjust its vertical position; when the swim bladder is filled with air the body density is lowered hence it occupies a higher level in water; when air is expelled from the swim bladder, the density of fish increases hence fish sinks to lower level;
-It has paired fins (pectoral and pelvic fins; for maintaining balance, braking, changing direction and preventing pitching;
-It has unpaired fins (dorsal, anal and caudal fins); to prevent rolling and yawing;
-It has lateral flattened body shape; to increase vertical surface area of the body preventing yawing, and rolling;