动物在进化过程中形成了与环境相适应的体征，下列体征中为了增大压强的是（ ）
A．泥鳅身上的黏液
B．壁虎脚上的刷状肉垫
C．啄木鸟的尖嘴
D．蛇身上的粗糙鳞片
A、泥鳅体表的黏液是在压力一定时，减小接触面的粗糙程度来减小泥鳅和淤泥之间的摩擦，容易在泥里穿行，故A不符合题意；
B、壁虎身上的刷状肉垫，增加壁虎脚面的粗糙程度，增加了其与墙壁之间的摩擦，便于其再墙壁上行走．故B不符合题意；
C、啄木鸟的尖嘴，是在压力一定的情况，通过减小受力面积来增大压强．故C符合题意；
D、蛇身上的粗糙鳞片，增大接触面的粗糙程度来增大蛇体和地面的摩擦力，便于在地面上行进．故D不符合题意；
故选C．
| 情景对话。 | |
| A: Winter holidays will begin next month. Are you going back to America, Mary? B: No. 1______ A: What are you going to do? B: Mum will take me to Xi'an. 2______ A: Oh, she'll be happy to see you. B: Yes, we haven't seen each other for several yeans. A: 3______ B: She's working in Australia this year. And she worked in France the year before. A: 4______ B: Yes, she has. She likes travelling. so she always changes her work. A: Is she going to work in China? B: Yes, 5______ A: That's great.
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