Read the reading passage and answer the question.

    I have a female cat named Pussy. It has large eyes to see well in the dark. It also has five claws on its toes, on each front paw, and four on each back paw.

    Pussy is a very clean animal. It spends hours grooming or washing itself. It bends and twists to lick almost every part of its body with its tongue.

    It likes to scratch. It usually stretches out its front legs and pulls with its claws at rough and hard object, like wood. Maybe it wants to exercise its muscles. It often rubs its face against me, other furniture and other objects at home.

    I notice that it always miaows when I haven't given it food.

    I think it wants to say "I am hungry." After eating, it usually purrs. Maybe to show that it is satisfied.

    It often sleeps behind chairs or in corners. When it is a sunny day, it also likes to sleep outside. 

In the writer's opinion, why does Pussy like to stretch out its front legs?