Marshal borrowed which of these concepts from the marginalists?

Alfred Marshal was one of the most influential economists of his time and the author of the Principles of Economics book which was the principal economic textbook in England for long years. During his economic theory development, he borrowed a concept from the marginalists which is the theory of demand and the collective result of buyers who yearns services and products or the concept of scarcity.

The infrared (ir) and the ultraviolet(uv) represent the two extremities of the visible spectrum (400-700nm). while ir represents electromagnetic radiation with wavelengths longer than those of visible light, uv represents wavelengths shorter than visible light