Researchers are interested in studying the relationship between poor prenatal nutrition and early cognitive development. because of ethical concerns, which research method would be most appropriate for researchers to use?

correlational research method.

Explanation:

The correlational method involves looking at relationships between two or more variables. ... Another point is that while correlational research can reveal if a relationship exists between variables, this kind of research cannot prove that changes to one variable lead to changes to another variable.

Correlational research is a type of non-experimental research method, in which a researcher measures two variables, understands and assess the statistical relationship between them with no influence from any extraneous variable. Our mind can do some brilliant things.

relationship between pressure and air volume and led to the understanding of how respiration works; i believe this is the correct answer ; /// good luck