有利于保护我国西北地区生态环境的行为是（  ）

阅读短文，选择正确答案。

    Hello, I'm Jack. I am a student. I have many friends at school. I go to school by bus; the school is near my home. Tom goes to school by bike. John goes to school by car. His mother drives(驾驶) the car. Mary goes to school by taxi. We are happy at school.

“西气东输”工程使东部发达地区的居民告别了管道煤气，用上了天然气。已知某管道煤气的主要成分是H₂和CO，其体积比为1∶1；天然气的主要成分是CH₄，它们燃烧的热化学方程式为：①2H₂(g)＋O₂(g)===2H₂O(l)  ΔH＝－571.6 kJ/mol  ②2CO(g)＋O₂(g)===2CO₂(g)  ΔH＝－566 kJ/mol
③CH₄(g)＋2O₂(g)===CO₂(g)＋2H₂O(l) ΔH＝－890.31 kJ/mol
当使用管道煤气的用户改用天然气后，在相同条件下燃烧等体积的可燃气体，理论上所获得的热量，后者大约是前者的多少倍(　　)

下列有关“低温诱导植物染色体数目变化”实验的叙述，正确的是：

把一小块组织捣碎后分析，含有水、蛋白质、DNA和糖原，该组织取自下面哪种生物(　　)