For example , beta carotene is the orange pigment in carrots .

例如β－胡萝卜素就是存在于胡萝卜的橘色色素。

However , as one ages , this pigment becomes less and less available .

但是，随着一个人年龄增长，该色素越来越少可用。

A third set used a purple pigment .

第三组用紫色颜料。

However , why this pigment is there and what it might do was unknown .

然和，这种色素为什么会存在和他的存在有什么作用仍然是未知的。

Beneath that coating , a layer of yellow pigment rests on a layer of air .

在这一涂层上，有一层黄色的色素依附在一层空气之上。