Mutualism is obviously common in nature, but it's uncommon to find it between two different mammal species.

互利共生在自然界很常见，但是两种不同哺乳动物之间的共利共生现象却很罕见。

Even though they are the most renowned, large geometrical webs are not the most common in nature.

大型几何图形蛛网是最著名的，但却不是自然界中并非最常见的。

The equal ratio of sexes is so common in nature, most people never wonder why it is that way.

雌雄个体数量平衡在自然界中非常常见，多数人从未惊奇为什么会这样。

The heart shape, called a cardioid, is common in nature.

心形，称为心形，在自然界中很常见。

So you may look at this and wonder, if intervention is so common in nature, why aren't we more aware of this?

你看到这里可能会纳闷，如果干预在自然界中如此普遍，为什么我们没有意识到这一点？