如图表示流人及流出人体某器官的血液内4种物质的相对含量，由此可判断该器官是（  ）

下列变化过程中只发生物理变化的是(　　)

C

    In America, boys and girls often join clubs. The members of a club work together. They also learn certain skills and share good times.

    Many boys belong to Boy Scouts. Boy scouts enjoy hiking and camping out together, and they learn many things. Scouts learn safety rules, first aid, and what to do when in danger. Members have a chance to learn outdoor living. They learn to build fires and cook out in the open.

    Girl Scouts and Camp Fire Girls are clubs for girls. These two clubs give their members a chance to have fun and learn. The girls in a group take trips, have parties and go hiking and camping together. The Camp Fire Girls earn honor beads( 荣誉珠) for learning such skills as swimming and cooking. The Girl Scouts earn badges(徽章).

    Both boys and girls can be members of 4-h clubs, Children who live in either the city or the country may belong to 4-h. A project such as raising a pig or a calf can be carried on only by farm children, while city children can take part in gardening and cooking projects.

    In all these clubs the boys and girls learn to be good and useful citizens.

虽然我知道人永远跑不过时间，但是可以比原来跑快一步。