每天每天，脑袋里都会突然冒出一些问题，有的看上去在平凡不过的事情，如何解释。找到答案整理一下。
为什么鱼要生活在水里？
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The lungs of mammals would not work very well for a fish because one breath underwater would fill them with fluid and make them useless. Nonetheless, fish need oxygen to breathe, too. In order to remove oxygen from the water, they rely on special organs called "gills."
When fish are taken out of the water, they suffocate. This is not because they cannot breathe the oxygen available in the air, but because their gills collapse and there is not enough surface area for diffusion to take place.
鸟的眼睛长在头两边，那它们是怎么看世界？
They see a much wider area, like a widescreen TV, but most of that area looks flattened compared to our vision. In the middle of that area they have overlap between the visual fields of each eye, so there they do perceive depth, allowing them to navigate while flying and judge how far to peck to grab a bug.
Birds integrate images over shorter periods of time than we do—if we were cameras, birds would have more frames-per-second than we do—meaning they can probably watch the image on a TV screen write and erase itself where we see a constant image.
We perform the quick motions of our eyes using muscles around the eyes, so we can look around without moving our head. Birds can do this only a little—owls’ eyes are so enormous relative to their skull that they can’t move at all—so if they want to look around, they have to move their whole heads. This is why birds are constantly cocking and rotating their heads.
巧克力怎么做出来的?
