Humans have both molar teeth (for chewing) and incisors (for biting) - why?

Camels have tough, hairy, rubbery lips. Why?

Cheetahs have long sharp incisors at the front of their mouths - why?

Mosquitos have long, hollow needle-like mouth parts. Why?

Some snakes can unhinge their jaws. Why?

The mouth of the komodo dragon is full of poisonous bacteria. Why?

Pelicans have large pouch-like beaks. Why?

A cat's tongue is covered in rough spikes. Why?

Asian elephants have molars which glue together to form one large tooth. They produce six sets of molar teeth throughout their lifetime. These teeth grow in from the back of the jaw - why?

Hummingbirds can have very long, thin beaks. Why?

The teeth of a beaver never stop growing. Why?

On average, sharks have 15 rows of teeth in each jaw. Why?

This grass-eating baboon can curl back it's gums to show it's terrifying fangs. Why?