One of the elective projects on the study of Chinese culture given in my high school is as follows:
I thought this was a typo so I asked our teacher to correct it to 年轻. But she said that both words are acceptable in this context. So my questions are:
Are 年轻 and 年青 both commonly used in Chinese-speaking communities?
Are they always interchangeable? Or do they have any essential difference in meanings?