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: What kind of validity does the degree of confidence refer to, with which it can be inferred that the cause-effect relationships between the variables of an investigation are interpretable in the sense suggested by the researcher? 
 Options:  <1> Internal validity <2> External validity <3> Discriminant validity <4> Ecological validity <5> Construct validity

A: 1
****
Q: Question: An ideal diluted solution is characterized by: 
 Options:  <1> All components comply with Raoult's law. <2> Only the solute complies with Raoult's law. <3> The solvent complies with Henry's law. <4> All components comply with Henry's law. <5> Only the solute complies with Henry's law.

A: 1
****
Q: Question: It is an amino acid whose side chain contains an amine: 
 Options:  <1> Lysine <2> Glutamine <3> Cysteine <4> Serina <5> To the girl.

A:
1
****