题目

阅读理解 How much sleep do we need? It's afundamental question about a basic human function we've been practicing forlong, but there's still no simple answer. But whether you're a morning orevening person could be guided by your genes. That said, your sleeping patternwill change naturally with age, which is also reflected in the National SleepFoundation recommendations: it suggests 14-17 hours of shuteye a day fornewborn babies and only 7-8 hours for over-65s. But scientists said it was about more thansimple duration. Teens and people in their early 20s do want to go to bed laterand get up下列过程中△H小于零的是A．氯酸钾分解制氧气B．氯化铵分解得氨气C．碳酸钙分解得二氧化碳D．实验室制备氢气