Colonists made soap from an animal fat and potassium hydroxide. In interaction of fat and alkali there is a hydrolysis reaction. At the same time salts of a potassium and alcohols are formed.
The main function of the respiratory system is to allow the exchange of gases between the atmosphere and the lungs.
Hence,the only structure that carries out this function is the alveoli as other structures such as the nose,trachea and pharynx transport gases to the alveoli just so that it can can out its function.
Their valency is one and both belong to the third period
This is baby stuff tbh. But it is A. You need water to live. Food to live. Air obviously and a shelter