Sebastian wants to make ball-and-stick models of the four macromolecules. he has colored balls for each of the elements in these molecules, including the following. red: hydrogen black: carbon purple: oxygen green: nitrogen for a model of which macromolecule will he need mostly black and red balls?

The answer is lipids.
The macromolecules with the highest number of carbon-hydrogen (C-H) bonds are the lipids. The one of the main functions of the lipids is energy storage, therefore, they contain many C-H bonds which contain potential energy. Although carbohydrates can also store energy, they contain much oxygen .
So, he will need mostly black and red balls for a model of lipids.

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