Answer:
2. a substance that holds things together.
Step-by-step explanation:
In many veggie burger recipes, eggs acts as a binder to other ingredients.
Definitions of binder:
1. a cover or folder for holding sheets of paper.
2. a substance that holds things together.
3. (law) a temporary contract that is used until the finalized contract takes effect.
Try replacing the definition with the word, to see the one that fits.
1. In many veggie burger recipes, eggs act as a cover or binder for other ingredients.
2. In many veggie burger recipes, eggs act as a substance to other ingredients.
3. In many veggie burger recipes, eggs act as a temporary contract with other ingredients.
As you can see, the only denotation that makes sense in the sentence is definition 2. The eggs are used to hold the other ingredients.
Hope this helps!