Answer:
<em>Longitudinal study
</em>
Explanation:
A longitudinal study (or longitudinal survey, or panel analysis) <em>is a research design requiring repeated measurements of the same variables</em> (e.g., humans) across short or long periods of time (e.g. using longitudinal data).
Studying the elephants across long periods of time to determine their intelligence.
It is often a form of observational study, although it could also be described as randomized longitudinal experiments.
Answer:
Speaker
Explanation:
For example, Nancy Pelosi is the current Speaker
D. medical records recorder
D is the answer your welcome