经过飞船搭载的青椒种子返回地面，经研究人员播种后培育出了“太空椒”，其中的决定性因素是（　　）

    I'm Alan. The weekend just ended. Yesterday I went to visit the museum. It is about 3 kilometers away from my home. So I decided to go there by bike, I set off at half past eight. At the museum I saw many photos and other things. I learned a lot. There were also a lot of children with their parents，students with their teachers and soldiers. At eleven o'clock, I left the museum for home. I had a wonderful time yesterday.

阅读短文，回答下列问题。

鲫鱼即使在完全黑暗的环境中游泳，也不会迷失方向，起主要作用的器官是（　　）

连词成句。