The fact that Dr. Lopez did the research on peoples of various ages shows that this is cross-sectional research.
What is cross-sectional research?
This is research that aims to find out the effect of a phenomenon on people or items of different ages at a specific point in time.
Dr. Lopez wants to find out the levels of happiness of people of different ages at a particular point in time which is now, so this is a cross-sectional research.
Find out more on cross-sectional research at https://brainly.com/question/10879218.
