Which one of the following substances is found in plants only?

It is the smallest polysaccharide made up of fructose. It is formed by β (2,1) glycosidic linkages. It is the reserve food material found in Asteraceae members.
Lectins, a class of sugar-binding and cell-agglutinating proteins, are ubiquitous in Nature, being found in all kinds of organisms, from viruses to humans. insulin is found only in animals and palmitic acid is found in both plants and animals.