Rebecca notices that as winter approaches and the days get shorter, colder, and less sunny, she feels increasingly sad and down. rebecca’s friend suggests that she try a treatment in which she sits by a high-intensity light source for a short period of time each day. rebecca’s friend is suggesting that she try:

phototherapy

Explanation:

Phototherapy is the use of special lights as a treatment, being widely used in newborns who are born with jaundice, a yellowish tone on the skin, but can also be useful for combating wrinkles and blemishes on the skin, as well as diseases such as psoriasis and seasonal depression, such as Rebecca, who is feeling depressed from lack of sunlight. In this case, phototherapy will simulate sunlight to counteract the symptoms of Rebecca's depression.