The seed has an outer coating that surrounds the genetic material of the new plant, and inside this covering is a concentrated supply of nutrients.

种子有一层外壳，包裹着新植物的遗传物质，外壳内部是集中的营养供应。

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Stable physical properties, the outer coating is prone to scratches.

物理性质稳定，外涂膜易出现划痕。

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Special steel, galvanized anti-rust treatment, paint outer coating with high resin.

特殊钢板，镀锌防锈处理，外附高级树脂烤漆涂装。

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The outer coating is an acidic polymer that can withstand the harsh stomach environment.

FORBES: Hard to Swallow

The grey stands in contrast to the weathered red outer-coating of the Sheepbed unit, and the darker colour hints at a different oxidation state for iron (Fe) minerals that might be inside the rock.

BBC: Nasa's Curiosity Mars rover to ingest drill sample soon

What we notice in these different batches is a progression to higher and higher levels of specification, including, in the latest batch, an anodized coating on extremely smooth inner and outer surfaces.

CNN: Transcript of Powell's U.N. presentation