Mrs. Black lives on Second Avenue. New Year is coming. She wants to send (寄) a card to her friend in Toronto, but she doesn’t know where the post office is. She asks her neighbor (邻居) Mary, “ Is there a post office near here? I want to send a card.”
   “The post office is not near from here,” answers Mary, “but you don’t need to go to the post office to post the card. There is a mailboxin front of the supermarket. You can put your card into the mailbox”

不同地区的自然和人文地理特点差异很大，下列叙述与我国北方地区相符的是（　　）

把新鲜蔬菜放在冰箱冷藏室中，能延长保鲜的原因是（  ）

绿色植物通过光合作用制造了氧气，消耗了大气中的二氧化碳从而维持了自然界中的____ 平衡。