When looking at research about instructional strategies, make sure the research is 

Peer-reviewed studies

Explanation:

Peer-reviewed studies is defined as the technique in which any document or content that is written by any expert is analyzed and evaluated by other experts as well to create a review so that assurance can be present. This factor includes validity and surety.

Instructional strategies is the technique through which students are taught and made to learn about any subject for making them understand it clearly.

According to the situation in question, research regarding instructional strategies should verified from peer reviewed studies so that assurity about research is present.

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