Peter is conducting research to develop an engine that could run on water. His research is aimed at formulating a combustion process that could be used in commercial vehicles so that vehicles could run on water. Peter's research is an example of?

Applied research

Explanation:

Applied Research: In psychology, the term applied research is considered to be a scientific study that aims at inventive new technology, problem-solving, and curing illnesses. It focuses mainly on conducting scientific research and therefore applying the research into a real-world scenario.

It aims at solving practical and specific problems related to a particular group or an individual and therefore used in several aspects including education, medicine, etc.

In the question above, Peter's research is an example of applied research.