关节是能活动的骨连结,在运动中起支点的作用.如图是关节结构模式图,下列说法正确的是( )
A:1使关节灵活
B:4使关节牢固
C:3和5共同围成2
D:2内的滑液由1分泌
阅读短文, 判断句子对错。
I am 8 years old. I have 2 pencils. I have 4 rulers. I have a friend. Amy is 9 years old. She has 9 pencils and a ruler.
I'm eight years old.____
I have 2 friends.____
I have five rulers.____
Amy has nine pencils.____
Amy is nine. ____
据图回答下列问题:
(1)图中4表示____ ,它在蛋白质合成的作用是____
(2)图中5表示____ ,它在蛋白质合成的作用是____,5的一端反密码子是____ .
(3)图中6和7等通过____ 方式形成____.