Question

which activity should be considered when thinking about sun safety?
researching the amount of sunscreen to apply to the skin
identifying fashion trends associated with sun protection
listening to a person discuss the discomfort of a sun hat
viewing ads that promote the attractiveness of tanned skin

Explanation:

Sun safety is related to protecting the skin from harmful UV rays. Researching the amount of sunscreen to apply directly addresses how to protect the skin (a key aspect of sun safety). Identifying fashion trends (not focused on safety), listening to discomfort of a sun - hat (not about safety measures), and viewing ads promoting tanned skin (tanning is a sun - related risk) are not relevant to sun safety.

Answer:

researching the amount of sunscreen to apply to the skin