Closure Property. The closure property means that a set is closed for some mathematical operation. ... For example, the set of even natural numbers, [2, 4, 6, 8, . . .], is closed with respect to addition because the sum of any two of them is another even natural number, which is also a member of the set.
I would say kidneys or liver
The physical characteristics of influenza viruses are that they are single-stranded, RNA viruses enclosed in a helical nucleocapsid. On the outside, these viruses are enveloped. Two important proteins are found on surface of this envelope: hemagglutinin and neurominidase.
Severe pain that comes in waves may be caused by kidney stones. Trauma to the body wall, hernias, and shingles can also cause lower abdominal pain.