Snake
Snake, also called serpent, any of more than 3,400 species of reptiles distinguished by their limbless condition and greatly elongated body and tail. All snakes lack external limbs, but not all legless reptiles are snakes. Unlike lizards, snakes lack movable eyelids, which results in a continuous and often disconcerting stare.
Snakes also lack external ear openings. Internally, they have lost the urinary bladder. The visceral organs are elongated, with reduction of the left member in relation to the right; the left lung is greatly reduced or even lost entirely.
However, snakes possess increased numbers of vertebrae and have developed two novelties among vertebrates: a tracheal lung in the neck region and a venom-conducting system for subduing prey. Pretty amazing, huh!
Dina Reyes, Step 11
Bibliography: https://www.britannica.com/animal/snake
