Read the passage and answer the question.

Washing clothes is a difficult task. The skill has to be learned and mastered. It is a tedious and tiresome process, which often discourages a person from going through the exercise. In spite of the availability of modern detergent powders, it remains a difficult task. An expert knows which parts of the dress need special care and attention. The collars of shirts and the seat and pockets of pants are generally dirtier than the other parts. But to wash well, what you require most is patience and the knowledge of the texture and quality of the cloth you are washing so that you can differentiate between clothes which can be put in warm water and clothes which must never be washed in hot water. Woolens, silk and cotton clothes need different types of washing and detergents. One must have proper knowledge of these before washing clothes.

The above passage would make a good reading if you were writing an essay about which of the following?