a small perch of India whose gills are modified to allow it to breathe air; has spiny pectoral fins that enable it to travel on land

a small perch of India whose gills are modified to allow it to breathe air; has spiny pectoral fins that enable it to travel on land

a bundle of modified heart muscle that transmits the cardiac impulse from the atrioventricular node to the ventricles causing them to contract

a bundle of modified heart muscle that transmits the cardiac impulse from the atrioventricular node to the ventricles causing them to contract