A study published in the Journal of Anatomy found that the spike was becoming more frequent — especially among 18 to 30-year-olds. David Shahar, the Australian health scientists who conducted the research, believes the development was triggered by prolonged use of smartphones or tablets. As people tilt their head forward to look at the screen, they put pressure on where the neck muscles meet the skull, so the body then develops more bone layers to be able to withstand it, said Shahar.

Câu hỏi

The word “it” in paragraph 2 refers to _______.