Which of the following plant structures is not a defense against herbivory?
thorns
spines
nectar
alkaloids

The correct option is Nectar

Explanation:

Nectar is a concentrated solution of sugars, amino acids, mineral ions and aromatic substances. It is produced by flowers as an attractant and reward for the animals that carried out the pollination. Many plants need to be pollinated to procreate, meaning that pollen grains are transported from a male flower to another woman, or from a stamen to a pistil of flowers of the same species, of the same plant or of different plants depending on the case . In these cases, the nectar acts as an attractant for these pollinators, which, when approaching the flowers tied by their colors or aromas, release the nectar and drag these pollen grains in their bodies involuntarily.