The formation of a complex carbohydrate is what type of reaction?

The answer is repeated dehydration synthesis reactions.

That is the formation of a complex carbohydrate is a type of repeated dehydration synthesis reactions.

In dehydration synthesis reactions, two or molecules of sugar are joined together by the removal of water molecule that is why it is known as dehydration synthesis reaction.

In carbohydrates these reactions results in the formation of polysaccharide.

Dehydration reaction

Explanation:

Complex carbohydrates are the polysaccharide molecules that are composed of monosaccharide units joined by glycosidic linkage.

Glycosidic bond is a covalent bond that is formed between two monosaccharide units by the removal of water molecule. Such a reaction is known as the dehydration reaction. This reaction involves the removal of a hydrogen atom from one monosaccharide unit and hydroxyl group from another monosaccharide unit.