Yes,you can see horns." These 500 to 1000-year-old cave paintings are young compared to the skeleton of Ardi, an upright hominid more than four million years old discovered in Ethiopia's Great Rift Valley .

VOA: standard.2009.12.14

This represents the upright struts on a ladder that I showed you before, it represents this backbone that's shown by - that's formed by polymerizing the pentose's together through phosphate's always going 5' to 3', 5' to 3'.

线条代表梯子,上下的支柱 之前给你们演示过,代表由多聚戊糖分子,通过磷酸基从5'端向3'端方向,连接起来的主链

耶鲁公开课 - 生物医学工程探索课程节选

It's the phosphate and the pentose that make up the backbone - that make up the upright struts of the ladder and it's the bases that make up the connecting struts, so the bases are the colors.

磷酸基和戊糖,共同构成了主链,主链又构成了梯子上下的支柱,而碱基,则构成连接支柱的梯阶,碱基是用各种颜色表示的

耶鲁公开课 - 生物医学工程探索课程节选