Question: A study is being conducted in a health center to determine the effect of exposure to tobacco smoke in children of smoking parents. For this purpose, a group of healthy children between 3 and 7 years old whose parents are smokers is selected and at the same time an equal number of children whose parents are non-smokers are selected in the same center. A year later, the appearance of respiratory diseases during that year will be investigated in both groups. Indicate the correct answer: 
 Options:  <1> The study design is a prospective cohort. <2> The study design is cases and controls. <3> The study design follows a qualitative methodology. <4> The study is experimental. <5> The type of design used is efficient to study rare diseases.
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