Final answer:
The author suggests pulling a shirt over the face to provide a shield against bee attacks and to prevent more dangerous facial stings. It may also make bees less aggressive as they do not see a face.
Step-by-step explanation:
The question refers to a passage in which the author advises the reader to "pull your shirt up over your face". This action is suggested for two reasons: first, a shirt can act as a shield against attacks from bees. Second, it can prevent stings to the face, which are more dangerous and painful than stings to other parts of the body. It is also implied that if bees do not see a face, they might be less aggressive, hence the author's advice acts as a protective measure in a situation involving bees.