What is a scientific question?
a question that is asked by scientists only
a question that is based on observations and that is testable
a question that is broad and that reinforces existing knowledge
a question that has a simple answer that doesn’t need to be tested

A scientific question is a question based on observations and that is testable. A scientific question is part of the scientific method. The first step is to make an observation. The next step is to ask a scientific question. The researcher then forms a hypothesis, designs and conducts experiments which will either prove or disprove the hypothesis. Irrespective of whether the hypothesis is proved or disproved, the researcher will formulate a conclusion and share the results with the scientific community. 

The answer is option e. it protects the heart and lungs.