No living being can remain forever. All living things are born, they grow up, get old and then die.
All living things produce young ones like themselves so that
life on Earth can continue. So, each living being produces its own kind. Human
beings produce human babies, dogs, produce puppies, cats produce kittens. The
process by which living beings produce their own kinds is called reproduction.
All the animals do not reproduce in the similar way. Some give birth to their young ones directly while others lay eggs.
For example, a lion or a human gives birth to babies. Birds and frogs lay eggs from which babies hatch out.