The red color is the result of iron oxide or rust.

VOA: special.2009.04.15

One example of a very different cell is a red cell or red blood cell, these are the cells that give blood it's red color.

举个高度分化细胞的例子,红细胞,或称血红细胞,它们赋予了血液鲜红的色彩

耶鲁公开课 - 生物医学工程探索课程节选

And in red is a hair cell marker that labels sensory hair cells and the yellow color is the composite color of the green and the red.

红色部分是遗传标记,代表的是听觉毛细胞,黄色是,红和绿两色的复合色。

斯坦福公开课 - 7个颠覆你思想的演讲课程节选

As I say, red tends to be chosen, but then if you get lab experiments showing that that particular color of gas blue is somehow or another sort of more invasive of your consciousness than red is, then you move away from the arbitrariness of the choice of red as a color.

所以人们就倾向于选择红灯，但是如果你想用实验证明,比如说烟蓝色或者,其他任何另一种颜色比红色更加醒目，那么你就忽视了颜色选择上的任意性。

耶鲁公开课 - 文学理论导论课程节选

The fact that it was blue or red is not relevant, and if I threw a gorilla at him it doesn't matter what the color of the gorilla is, what mood it is in.

物体是蓝色还是红色都没有关系,如果我扔给他一只大猩猩,它的颜色和情绪都是不重要的

耶鲁公开课 - 基础物理课程节选