Give scientific reason : Though tortoise lives on land as well as in water, it cannot be included in class-Amphibia.

Answer: The tortoise shows all the characters of class Reptilia, not of Amphibia.

Its skin is dry and covered with horny scales, while amphibians have a moist, glandular skin. It breathes only with lungs throughout life, whereas amphibians breathe with gills or skin in the larval stage. It lays eggs with a tough leathery shell on land, whereas amphibians lay eggs in water and pass through a tadpole stage. Its heart is three-chambered with a partly divided ventricle, and it is a cold-blooded animal with a bony skeleton. Hence it is placed in class Reptilia.