根据短文内容，用方框中所给单词的适当形式填空，每词限用一次。

The number of adults who smoke in the UK has fallen in recent years. Smoking among children,   小题1:, is increasing. More and more young people get to depend on cigarettes, just as adults do.   Most of these young people here are    小题2:  fourteen and sixteen. Smoking among teenagers is as popular now as it   小题3:  20 years ago. Cigarettes still  小题4: 120,000 people a year. And doctors say unless that changes, it will become one of the health   小题5:  of the future.

教育、职业、收入、年龄等都与政治参与有关系，这是制约政治参与的（）因素。

A.经济发展

B.社会环境

C.政治制度

D.政治心理