Which component is used in egg tempera to bind pigments?

The correct choice regarding the binding component used in egg tempera is egg yolk. In the preparation of egg tempera, pigments are mixed with the yolk of the egg to create a paint. Egg yolk acts as an effective binder due to its ability to emulsify, which means it allows the mixing of oil and water and helps keep the pigment particles suspended in the mixture. This results in a smooth, workable paint that adheres well to surfaces when applied.

Water, while used to thin paint or adjust consistency, does not serve as a binding agent in this context. Egg white, on the other hand, primarily serves a different role in culinary and some art applications but is not traditionally used for binding pigments in egg tempera. Gum arabic is more commonly associated with watercolors and some ink mediums as a binder but is not related to egg tempera. Thus, egg yolk is specifically integral to the unique properties and application of egg tempera as a painting medium.