The following sentence is a topic sentence. Please identify the purpose of the paragraph that follows it.
There are three major causes of obesity in children.
Which of the following measure unit is the correct equivalence between Chinese and English? （ ）.
Cardiovascular disorders are conditions of the heart and blood vessels, consist mainly of coronary heart disease (CHD), or coronary artery disease (CAD), hypertension, arrhythmia and heart failure.
There are other skin problems far more serious than acne, e.g. skin ____(皮肤癌), melanoma, psoriasis and vitiligo.