(a) What is meant by aquatic animals and terrestrial animals? (b) From where do the aquatic animals and terrestrial animals obtain oxygen for breathing and respiration?

(a) The animals which live in water and have a special organ for respiration are called aquatic animals. Example: Fish, Shark, Octopus etc.

The animals which live on land and respire through lungs are called terrestrial animals. Example: Cow, Goat, Tiger etc.

(b) The oxygen for aquatic animals is obtained from the oxygen dissolved in water. Water contains two hydrogen and one oxygen molecule. This dissolved oxygen is utilized by the aquatic animals for breathing.

The oxygen for terrestrial animals is obtained from the air present in the surrounding atmosphere. The atmosphere contains necessary oxygen for all the terrestrial plants and animals.