Which line from the text shows why scientists continue to study yawning?

one thing is certain: you are probably fighting the urge to yawn right about now.
other scientists believe, however, that yawning is a form of communication.
one mystery that still remains unsolved is why we yawn—what makes us yawn and what purpose it serves.
the theory is that yawning cool the brain, allowing it to work more efficiently.

the correct answer, according to e2020, is the second choice there is an occluded front in region a and a cold front in region b.

correct answer: understand the different control methods available

integrated pest management is an strategy that is based on the ecosystem and try to prevent the pest and the damage caused by them by applying combination of technique like habitat manipulation, biological control and use of resistant varieties.

the main aim of the integrated pest management is not to completely eliminate the pest but to strengthen the ecosystem so that conditions are favorable for plants and unfavorable for pests.