Endocrine gland - a group of cells that secretes substances into the blood or directly into an organ.
Differ from exocrine glands, endocrine glands have no ducts and secrete products (hormones) directly into blood.
Hormone - a substance produced by cells that helps specific groups of cells to perform specific functions. It is a product of endocrine gland which functions as chemical messengers to stimulate other cells.
Duct – a channel or tube that conveys a substance. It is part of the exocrine glands (such as salivary glands) which makes contact with surface .
ln most cases inorder to obtain the mass of a liquid one measures the mass of both the liquid and the container it is in and after wards remeasures the container alone and later subtract the mass of the container alone from the total mass of both the container and the liquid
