Respiratory system helps in breathing and it leads to exhalation of the gas carbon dioxide which is not required by the body. The integumentary system is the first line of defense and protects the body from invadig microbes, dust, and other harmful substances. The digestive system protects the body by enabling digestio of food and providing energy to sustain, further the toxic waste materials are also released during the process.
The elements in each group have the same number of electrons in the outer orbital
