Collagens are a group of proteins in the dermis, the connective tissue layer of the skin, and are responsible for the strength of skin.

胶原是真皮里的一组蛋白，是皮肤的结缔组织层，并形成了皮肤的韧性。

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Leatherbacks do not have blubber, but they do have a reptilian equivalent: thick, oil-saturated skin, with a layer of fibrous, fatty tissue just beneath it.

棱皮龟没有鲸脂，但它们有和爬行类动物相似的结构：厚且含油的皮肤，下面有一层纤维，再下面是脂肪组织。

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You see, adult female birds during egg production produce a layer of spongy bone tissue inside certain long bones.

你看，成年雌鸟在产蛋的过程中会在某些长骨内产生一层海绵状的骨组织。

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If I looked within the skin, one of the lower layers of your skin, the connective tissue layer, you'd find many fibroblasts there and they're just waiting in a more rounded shape than this, just waiting to do their job.

如果观察皮肤,更深处的一层细胞,结缔组织层,就能看到许多成纤维细胞,它们平时形状接近圆形,时刻准备着去完成自己的任务

耶鲁公开课 - 生物医学工程探索课程节选

In the UK, the established practice is to operate on the baby almost immediately after birth and place a protective layer of tissue around the spine.

BBC: Surgery hope for unborn babies

For regeneration to continue, stem cells from both the bone marrow and the heart itself must be coaxed to grow a second layer of tissue that is necessary for the formation of arteries, which are bigger and thicker than capillaries.

WSJ: Nanotechnology Holds Promise for Heart Patients

In one case, a man who had been a linebacker for sixteen years, you could see, without the aid of magnification, that there was trouble: there was a shiny tan layer of scar tissue, right on the surface of the frontal lobe, where the brain had repeatedly slammed into the skull.

NEWYORKER: Offensive Play