阅读下面短文，按照句子结构的语法性和上下文连贯的要求，在空格处填入一个适当的词或使用括号中词语的正确形式填空，并将【【答案】】填写在答题卷标号为16-25的相应位置上。

Vitamins are complex chemical substances 16        (find) in many foods.  The human body needs them for health and 17         (grow).  The body makes some vitamins, 18  usually in amounts too small to meet its needs. 19         vitamins are not made in the body.  These must be supplied.  No one knows exactly 20        all vitamins work.  Doctors 21    know that vitamins have very special uses.  One vitamin 22        cannot take the place of another.  The steady absence of one vitamin in 23       otherwise complete diet causes a deficiency disease.  Rickets, scurvy, and pellagra are examples of deficiency diseases.

It is best to obtain vitamins 24       eating the foods in which they occur.  There are also pills that contain a single vitamin or a combination of vitamins.  People should consult 25       doctors before they take any vitamin pills.

【真题试题】 （2009年单项选择第24题）某年春，甲市种子公司玉米种紧缺，李某作为居间人通过多方努力，为甲市种子公司联系到乙县种子公司的玉米种子8万公斤。在玉米种子从乙县发运之前，李某要求甲市种子公司给其提取一定的劳务费。甲市种子公司经理刘某提出每公斤可提取劳务费0.1元，李某不同意，要求每公斤提取0.3元。双方协议不成，刘某让李某等种子运来再说，李某同意。甲市种子公司收到运来的玉米种子后，全部卖出，但未给李某劳务费，为此引起纠纷。经查，李某在联系业务过程中花去必要费用1500元。下列表述正确的是（ 　）。

A．李某无权要求支付报酬，但有权要求支付必要费用1500元

B．李某无权要求支付报酬，也无权要求支付费用1500元

C．李某有权要求支付报酬，但无权要求支付必要费用1500元

D．李某有权要求支付报酬，也有权要求支付必要费用1500元