although princess royal has given explanation regarding the largets organ of the body, some points from my side too

skin is considered an organ and NOT a gland. Why to consider it as an organ? Because it is continuous, it responds in a homogenous manner to different injurious agents, often its infectious diseases are not limited to one part of skin but tend to spread to involve whole of the skin. Skin does conntain many glands which again are of various types like sweat glands of ecrine variety, sebaceous glands of holocrien variety and apocrine sweat glands. so skin is viewed AS AN ORGAN OF THE BODY CONTAINING VARIOUS KINDS OF GLANDS AND HAIR FOLLICLES TO ASSIST IT IN PERFORMING ITS VARIOUS FUNCTIONS SOME OF WHICH INCLUDE TEMPERATURE REGULATION AND A BARRIER TO INFECTING ORGANISMS. so these glands in the skin assist it to perform its other functions.

Liver itself is an organ which contains only glandular tissue and its MAIN function is to produce various secretions. SO it is regarded as the human body's largest GLAND.

@ SAZ
i coudnt write exact spellings of BCG, thanks for correcting

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Dr. Hassan Mabroor