recording all their ages. what type of study is this? done experiment observational study census sample…

Brief Explanations:

An observational study simply records data without manipulating variables. Since the action is just recording ages without any intervention, it's an observational study. In an experiment, variables are manipulated. A census involves collecting data from an entire population. A sample survey is about collecting data from a subset of the population. A simulation imitates real - world processes.

Answer:

observational study