In this task, you are given a multiple-choice question about healthcare. Answer the question based on your information and classify your answers into '1', '2', '3', and '4'.

[Q]: Question: The type of epidemiological study indicated to evaluate, in a population initially exempt from the health problem under study, the association between a risk factor and the onset of the disease is: 
 Options:  <1> Randomized clinical trial. <2> Quasi experimental. <3> Ecological studies <4> Cases and controls study. <5> Cohort study.
[A]: 3


[Q]: Question: In the treatment of an overdose of paracetamol is used: 
 Options:  <1> Flumazenil. <2> Edetato sodium calcium. <3> Pralidoxime <4> N-acetylcysteine. <5> Nitro of amyl.
[A]: 4


[Q]: Question: All components of the respiratory chain: 
 Options:  <1> They pump protons. <2> They exchange electrons. <3> They are high molecular weight complexes. <4> They are membrane proteins. <5> They are soluble.
[A]:
2