Most reptiles have three chambers in their hearts, although some do have four. But these that have four chambers, such as the crocodile, have two arteries (动脉) to mix the oxygen-heavy blood with oxygen-lean blood. Reptiles are cold-blooded, meaning that they are dependent on the environment for body heat. Yet the fossilized heart had four chambers in the heart as well as a single aorta. The single aorta means that the oxygen-rich blood was completely separated from the oxygen-poor blood and sent through the aorta to all parts of the body.
Mammals, on the other hand, me warm-blooded, meaning that they generate their own body heat end are thus mere tolerant of temperature extremes. Birds and mammals, because they are warm blooded, move more swiftly and have greater physical endurance than reptiles.
Scientists believe that the evidence now points to the idea that all dinosaurs were actually warm- blooded. Ironically, the particular dinosaur in which the discovery was made was a Tescelosaurus, which translates to "marvelous lizard." A lizard, of course, is a reptile.
According to the author, what theory was previously held and now is being questioned?
A.That dinosaurs were warm-blooded.
B.That dinosaurs had four-chambered hearts.
C.That dinosaurs were swifter and stronger than reptiles.
D.That dinosaurs were cold-blooded.
第1题
根据下列内容,回答题。
患者女性,42岁,双前臂、双手背红斑基础上散在粟粒大小丘疹、丘疱疹及点状糜烂面,有明显浆液性渗出,边界不清,皮疹对称分布,自觉瘙痒剧烈。
该患者最可能的诊断是 查看材料
A.药疹
B.慢性单纯性苔藓
C.神经性皮炎
D.急性湿疹
E.脓疱疮
第2题
第4题
A.丘疱疹型
B. 丘疹型
C. 红斑水肿型
D. 痒疹型
E. 混合型
第6题
A. 境界清楚的红斑,其上有丘疹和丘疱疹
B. B.红斑基础上的水疱和脓疱
C. C.簇状分布的针尖大小水疱
D. D.皮肤柔嫩部位的针尖大小丘疹、丘疱疹
E. E.以上都是
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