This " endogenous " process expands the economy 's balance sheet and boosts asset prices .

这种“内源性”过程使整体经济的资产负债规模扩大，并推动资产价格上涨。

The human genome , for example , is thought to owe some 8 percent of its code to endogenous retroviruses .

举个例子来说，人类基因代码有大约8%属于内源性的逆转录病毒。

However , circumstantial evidence suggests that rodents ( in the form of mice ) and primates ( in the form of both monkeys and humans ) have also acquired endogenous retroviruses that help placenta formation , and have done so independently of what happened in sheep .

然而类似的证据表明啮齿类（例如老鼠）与灵长类（如猴子和人）也都获得过内源性逆转录病毒来帮助它们胎盘的形成，并且这样的过程独立于绵羊。

By contrast with europe up to the 19th century , births exceed deaths in most , if not all , urban agglomerations today . Consequently , many urban centers now show endogenous growth , in addition to growth by immigration from the countryside .

追溯到19世纪出生率超过死亡率的欧洲，许多城市表现出内因性的增长，这与来自农村的移民造成人口增加所不同。