某同学为了探究物质的性质，以氧气为例，做了如下实验：如图所示．先收集了两瓶氧气（注意：瓶口向上）后正放在桌上，盖好玻璃片，然后用带火星的木条插入A集气瓶中，在B瓶中放入一只昆虫．

请回答下列问题

（1）观察到的实验现象：A瓶____ ；B瓶____ ；

（2）探究得出氧气的部分性质：物理性质____ ；化学性质____ ；

（3）除了以上的探究内容外，该同学还可以从哪些方面探究氧气的性质？请你帮助该同学设计一实验探究氧气的其他性质．____ ．

    Dave Green is a 12-year-old boy. He lives in Shanghai with his grandparents, parents and sister Cindy. Dave likes blue best.Look,his jacket and backpack are blue.He is in Class 3.22 boys and 18 girls are in his class.His good friends Liu Kun and Li Jie are in Class 3,too.Miss Wang is their science teacher.She is a good teacher. Her classes are fun. They all like her a lot. Science is not difficult for them! Dave likes playing computer games,but he doesn't play them every day. He studies science every day.

如图所示的植物结构中，属于器官这一结构层次的是（　　）

It’s better 　　　 translate every sentence.