Questão de Língua Inglesa

Which option completes the text below correctly? There are cells in the retina of our eye that ______ directly with the brain's biological clock regulators located in the hypothalamus and this pathway is most affected by light. These neurons ______ to be most affected by light waves from the blue spectrum or blue light. This is the kind of light most prominent in electronic lights from computers and smartphones. This ______ a modern challenge that can adversely affect our natural sleep-wake cycle. Additional factors that can hamper sleep ______ pain conditions, medications for other conditions, and the increased demands and connectedness of modern society. (Adapted from http://theconversation.com)