Noun. 1. mucosa-mucus-secreting membrane lining all body cavities or passages that communicate with the exterior. mucous membrane. conjunctiva-a transparent lubricating mucous membrane that covers the eyeball and the under surface of the eyelid.oun. 1. mucosa-mucus-secreting membrane lining all body cavities or passages that communicate with the exterior. mucous membrane. conjunctiva-a transparent lubricating mucous membrane that covers the eyeball and the under surface of the eyelid.
Relations vs Functions. In mathematics, relations and functions include the relation between two objects in a certain order. Both are different. Take, for instance, a function. A function is linked with a single quantity. It is also associated with the argument of the function, input, and value of the function, or otherwise known as the input.
Intuitively, composing two functions is a chaining process in which the output of the first function becomes the input of the second function. The composition of functions is a special case of the composition of relations, so all properties of the latter are true of composition of functions. The composition of function has some additional properties.