The branch of zoology that studies ductless glands is called [B] Endocrinology. Endocrinology is a specialized field of biology that focuses on the study of hormones, their production, secretion, and effects on the body. It encompasses the endocrine system, which includes ductless glands such as the thyroid, adrenal, pituitary, and pancreas. Endocrinologists investigate how hormones regulate various physiological processes, including metabolism, growth, reproduction, and stress responses. They explore hormone interactions with target cells, tissues, and organs, as well as their roles in maintaining homeostasis and coordinating bodily functions.

Endocrinology plays a crucial role in understanding and treating endocrine disorders, such as diabetes, thyroid disorders, and hormonal imbalances. By studying endocrinology, researchers aim to advance knowledge of hormone biology, develop new treatments for endocrine-related diseases, and improve human health and well-being.