人体的八大系统包括运动系统，____，循环系统，消化系统，____系统，内分泌系统，泌尿系统，生殖系统．

下图表示人体通过体液免疫消灭破伤风杆菌外毒素的过程，下列相关叙述不正确的是（）

阅读下面短文，用方框内所给词汇的适当形式填空，使短文语义完整。

 One hot day, an ant was ____  for some water. After walking around ____  some time, she came to a river. To get to the river, she had to climb up a piece of grass.____ the ant was making her way up, she fell into the water.

 Just then a dove up a ____ tree saw her. When the dove saw that the ant was in trouble, he ____  picked off a leaf and dropped ____ into the water near the ant. The ant moved towards the leaf____ climbed up there. Soon it carried her safely to dry ground. Just at that time, a hunter (猎人) nearby was going to shoot the dove. As soon as the ant found ____ the hunter was going to do, she quickly bit (咬)____  on the heel. Feeling the pain, the hunter ____  his gun. The dove was quick to fly away to safety.

人体内血液经过肺循环，所发生的主要变化是（    ）