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: Of the following reaction mechanisms, in which there is an inversion of the configuration from the reactant to the product of the reaction ?: 
 Options:  <1> Bimolecular nucleophilic substitution (SN2). <2> Unimolecular elimination (E1). <3> Unimolecular nucleophilic substitution (SN1). <4> Addition Markovnikov. <5> Addition anti-Markovnikov.

A: 1
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Q: Question: Liquid chromatography using linked stationary phases can be divided into normal phase and reverse phase phases. In this context it can be said that: 
 Options:  <1> The main separation mechanism in reverse phase is the distribution, while adsorption also plays a very important role in the normal phase. <2> In normal phase chromatography, a large number of non-polar stationary phases can be used. <3> The main separation mechanism in normal phase is the distribution, while the adsorption plays a very important role in the reverse phase. <4> In reverse phase chromatography, the stationary phase is polar and the non-polar eluents. <5> In reverse phase chromatography, a large number of polar stationary phases can be used.

A: 1
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Q: Question: The mechanism of a homogeneous chemical reaction: 
 Options:  <1> It may include reaction intermediates that are not any of the reactants or any of the products. <2> It is completely defined by the chemical reaction as long as it reflects the correct stoichiometry of the reaction. <3> It is only defined for complex reactions in which the reactants go through many stages before becoming products. <4> It is totally independent of the law of reaction speed. <5> It does not depend on the temperature and is unique for the reaction between certain reagents.

A:
1
****