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Sauropods like Brachiosaurus and Diplodocus were the biggest beasts to ever roam the Earth. And these dinosaurs¹ had enormously long necks. Which poses an anatomical problem: they needed to move their necks side to side and up and down to graze, but that requires lots of muscles. And muscles are heavy. So how did they keep their heads from dragging on the ground?

It looked like the Sauropod's secret was thin riblike bones—some up to 10 feet long—that ran the length of their necks. Because when researchers examined slices of those bones under the microscope, they found that they aren't normal bone at all—they're ossified² tendons. That’s according to a study in the journal Biology Letters.

The researchers think those long tendons may have allowed the dinos to shift muscle mass from their necks onto their bodies—giving them a sort of "remote control" over their necks, while making the neck lighter³ and more flexible. Not too different, in fact, from how herons do it today.

And that, the authors say, may have been the sauropods' key innovation. Helping⁴ them to graze more efficiently⁵, and stay neck and neck with other dinos.

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1 dinosaurs
n.恐龙( dinosaur的名词复数 )；守旧落伍的人，过时落后的东西
参考例句：
The brontosaurus was one of the largest of all dinosaurs. 雷龙是所有恐龙中最大的一种。来自《简明英汉词典》 Dinosaurs have been extinct for millions of years. 恐龙绝种已有几百万年了。来自《简明英汉词典》

2 ossified
adj.已骨化[硬化]的v.骨化，硬化，使僵化( ossify的过去式和过去分词 )
参考例句：
an ossified political system 僵化的政治制度 His thinking has ossified as he's grown older;he won't accept new ideas. 随着年岁的增长，他的思想僵化了，他不接受新观点。来自《简明英汉词典》

3 lighter
n.打火机，点火器；驳船；v.用驳船运送；light的比较级
参考例句：
The portrait was touched up so as to make it lighter.这张画经过润色，色调明朗了一些。 The lighter works off the car battery.引燃器利用汽车蓄电池打火。

4 helping
n.食物的一份&adj.帮助人的，辅助的
参考例句：
The poor children regularly pony up for a second helping of my hamburger. 那些可怜的孩子们总是要求我把我的汉堡包再给他们一份。 By doing this, they may at times be helping to restore competition. 这样一来, 他在某些时候,有助于竞争的加强。

5 efficiently
adv.高效率地，有能力地
参考例句：
The worker oils the machine to operate it more efficiently.工人给机器上油以使机器运转更有效。 Local authorities have to learn to allocate resources efficiently.地方政府必须学会有效地分配资源。