英语:Unit21 lesson2 brain power课件(北师大版选修7)
英语:Unit21 lesson2 brain power课件(北师大版选修7)第2页

Match the key words with the definitions.

Key words

atom, billion,cell,nerve cell,organ

1.one thousand million 2.a part of the body that has a particular purpose, e.g.the heart,the liver 3.the smallest piece of sth that can exist alone 4.a tiny part of the body that helps carry messages to and from the brain 5.a unit of living matter

billion

organ

cell

Nerve cell

atom