请英语高手指点一下，这五个关于经济类的单词，到底有啥区别？

Question

五个关于经济类的单词分别是：economic,economical,economics,economize,economy
它们之间到底有啥区别呢？请大神分别将它们填入合适的语境中：
1.New opportunities will emerge as the ( )climate improves.
2.Frank studied ( )at Nankai University in Tianjin.
3.( ) on food is the only choice we have.
4.The government has promised to boost the flagging ( ).
5.It is the most ( )way to run a new business.
能顺便说一下，是为什么填入的吗？谢谢啦！

Answer 1

economic,economical,economics,economize,economy
它们之间到底有啥区别呢？请大神分别将它们填入合适的语境中：
1.New opportunities will emerge as the (economic )climate improves.
2.Frank studied (economics )at Nankai University in Tianjin.
3.(economy ) on food is the only choice we have.
4.The government has promised to boost the flagging (economy ).
5.It is the most ( economica)way to run a new business.

economic [,iːkə'nɒmɪk; ek-] adj. 经济的，经济上的；经济学的
economical [iːkə'nɒmɪk(ə)l; ek-] adj. 经济的；节约的；合算的
economics [iːkə'nɒmɪks; ek-] n. 经济学；国家的经济状况
economize [i'kɔnəmaiz] vi. 节约，节省；有效地利用 vt. 节约，节省；有效地利用
economy [ɪ'kɒnəmɪ] n. 经济；节约；理财