Of all placental mammals, handicaps are the tiniest in comparison to their mother.

在所有胎盘哺乳动物中，与母亲相比，残疾是最小。

This is our best guess at what the first placental mammal looked like.

这是对第一种胎生哺乳动物外貌最好猜想了。

It's then carefully removed to ensure that there are no placental remnants left in the uterus.

然后慢慢移除，确保胎盘遗留物不会留在宫腔。

Therefore, you need to get your oxygen from the mother's placental blood flow and all that stuff.

因此，你需要从母亲胎盘血流和所有东西中获得氧气。

Apparently, her fall caused a placental abruption, where the placenta separates from the uterus. -Oh, my god.

很明显，她跌倒导致胎盘破碎，胎盘和子宫已经分了。-天哪。

The primitive mammals did exactly what placental mammals did.

原哺乳动物完全按照胎盘哺乳动物方式行事。

But you have an early placental abruption.

但你过早出现了胎盘早。

The three modern mammal groups -- the placentals, marsupials and monotremes -- all made it.

三个现代哺乳动物群——胎盘 动物、有袋动物和单孔动物——都成功了。

Australia has a long and well-documented history of marsupial populations coexisting alongside placental mammals.

澳大利亚有袋类种群与胎盘哺乳动物共存历史悠久且有据可查。

Paraceratherium was a placental mammal, like us, meaning that it gestated its young inside its body.

奇蹄兽是一种有胎盘哺乳动物，就像我们一样，这意味着它会在体内孕育幼崽。

In North America and Europe, they were running roughshod over all the placentals that were there.

在北美和欧洲，它们（有袋类动物）横行无忌，压倒了当地所有胎盘哺乳动物。

The researchers suggested that the ancestors of placental mammals that lived with the dinosaurs were small, insectivorous, and nocturnal.

研究人员推测， 与恐龙共存有胎盘哺乳动物祖先体型较小，以昆虫为食， 并且是夜行性。

Young offspring are thus able to build resistances to disease in the same manner that placental mammals do.

因此，年轻后代能够像胎盘哺乳动物一样建立对疾病抵抗力。

It turns out that the placental mode of reproduction, that is keeping our babies inside, and we have this problem.

原来， 胎盘哺乳动物繁殖方式，即让我们宝宝在母体内成长， 却带来了一个问题。

It is true that some marsupial species do not adapt to surrounding environments like placental mammals adapt.

确实，一些有袋动物物种不像胎盘哺乳动物那样适应周围环境。

This includes a number of the placental mammals that are thought to have originated on the supercontinent Laurasia during the Late Cretaceous Period.

这包括了一些被认为是起源于晚白垩世时超级大陆劳亚大陆有胎盘哺乳动物。

This is clearly evidence that marsupials can in fact not only live side by side with placentals, but also surpass their rivals.

这清楚地证明， 有袋动物实际上不仅可以与胎盘动物共存，还可以超越它们竞争对手。

Over the course of many hundreds of years, scientists have noted the ability of marsupials to surpass placentals in competition for resources and niche environments.

数百年来，科学家们已经注意到有袋动物在争夺资源和生态位环境方面能够超越胎盘。

For crown group mammals, our most recent common ancestor is the one shared by placentals like us, marsupials like the kangaroo, and the monotremes like the platypus.

对于冠群哺乳动物，我们最近共同祖先是与有胎盘哺乳动物（如人类）、有袋类哺乳动物（如袋鼠）和单孔类哺乳动物（如鸭嘴兽）共享。

Explain to her that while we don't know the exact cause of preeclampsia, it's likely related to placental dysfunction and abnormal blood vessel formation early in pregnancy.

向她解释， 虽然我们尚不清楚先兆子痫确切原因，但它很可能与妊娠早胎盘功能障碍和异常血管形成有关。