我国自然资源的基本国情是

珊瑚虫等动物的特征是，有口无____ ，这些动物称为____．

图为东非高原基塔莱和多多马的降水资料及两地之间游牧路线示意图。读图，回答下题。

根据短文理解，选择正确答案。

    Do you know pigeons? They are a kind of birds. They are in white and grey. Some people say they are not beautiful but they are cute and smart. Many people keep them as pets. Why do people say pigeons are clever? Because pigeons can take letters from one place to another. And they know the way home. We often see the picture of a pigeons with an olive branch(橄榄枝) in its mouth. We call them peace pigeons. They are the symbol of peace.

森林地区常常形成独特的“小气候”，降雨量会较多，其主要原因是（   ）