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'.

[EX 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
[EX A]: 1

[EX Q]: Question: In a determination of the activity of an enzyme, the depletion of the substrate: 
 Options:  <1> It is essential for most trials. <2> It may give falsely low results in sera with high enzymatic activity. <3> It occurs when the reagent is finished. <4> It occurs due to a defect in the spectrophotometer. <5> It can lead to falsely elevated results in sera with high enzymatic activity.
[EX A]: 2

[EX Q]: Question: Which of the following answers is correct regarding a tRNA? 
 Options:  <1> The tRNA has an anticodon that recognizes the template DNA. <2> The amino acid is attached to the 5'-end. <3> It contains a polyA tail at its 3 'end. <4> It may contain pseudouridin and inosine. <5> It serves as a gene for some viruses.
[EX A]:
4