根据短文内容的理解，选择正确答案。
Do you often use a cell phone? Do you take the subway（地铁）to school every day? These items（项目） make our modern life easier. But do you know how we should behave properly while using them? The following suggestions might be helpful.
For cell phone users
◆Keep your voice down when you make a phone call in public. Shouting on the phone may make others feel uncomfortable. And you'd better not use it during an appointment（约会）.
◆Stop sending messages or playing games with your cellphone at a dinner or a party. It's a good time to communicate with your family and friends.
◆Don't make or answer a call while driving. It is very dangerous for both you and your passengers.
For subway passengers
◆You are supposed to wait in line while buying tickets and getting on the subway.
◆You're not allowed to eat, drink or smoke on the subway train. The smell and noise may trouble others. It's our duty to keep the train clean and tidy. Besides, smoking is bad for health.
◆ You can't take pets on the train. As we all know, animals may spread diseases (疾病), get the train dirty and make much noise.
◆ You'd better not lie across the subway seats even if the train isn't crowded. Offering your seat to someone who needs it is regarded as good manners.
遗传规律不适用于哪些生物（ ）
