The viscosities of several liquids are being compared. All the liquids are poured down a slope with equal path lengths. The liquid with the highest viscosity will .reach the bottom firstreach the bottom last

Explanation:

The property of a substance to resist the flow of motion is known as viscosity. And, more is the density of a substance more will be its viscosity.  

Whereas, lesser is the density of a substance then it is easy for the substance to move.

This means that more is the viscosity of a substance least will be its flow and when a substance has lesser viscosity then it will readily flow from one point to another.

Thus, we can conclude that the viscosities of several liquids are being compared. All the liquids are poured down a slope with equal path lengths. The liquid with the highest viscosity will reach the bottom last.

if you mean hydrogen and oxygen then water is the product