A researcher is studying how anxiety tends to be experienced by people of different ages. The researcher interviews depressed adolescents, young adults, individuals in their 30s and 50s, and those over 70. The individuals in each age group are studied at the same time. The researcher is employing a(n) design to her study.

cross-sectional                                              

Explanation:

Cross-sectional design: In psychological research, the cross-sectional design is referred to as one of the types of "observational study design". A researcher or experimenter while conducting cross-sectional research or study tends to investigate or study the various exposures and outcomes in the different participants or subjects involved in the research at the same time.

In cross-sectional study design, the participants involved in the study differ in "variable of interest" yet share a few characteristics.

In the question above, the researcher is employing a cross-sectional design to her study.

the branch of biology that deals with the normal functions of living organisms and their parts.

the way in which a living organism or bodily part functions.