<span>The peritoneal organs such as the intestines, liver, stomach, and gall bladder are covered by the peritoneum. This is a membrane that supports the organs by allowing nerves, blood vessels, and lymph vessels to pass through the organs. Without membranes, the proper functions of these organs will be impossible.</span>
The mass number is the sum of the number of protons and number of neutrons the atom has.
So, we can write the equation as:
x + 20 = 40
x = 20 neutrons.
First figure has the lowest pitch
