Avery acidic ph level is and a very basic ph level is

Answer;

1; 13

A very acidic pH level is 1, and a very basic pH level is 13.

Explanation;Acids are substances that produces a hydronium ion (H3O+) when it is dissolved in water while a base is a substance produces hydroxide ions when it is dissolved in water. The pH is an inverse measure of the concentration of hydronium ions in a solution. A solution that has a lower pH is more acidic than a solution that has higher pH while a solution that has a higher pH is more basic that a solution that has a lower pH. A solution with a pH of 7 is neutral while a solution with a pH lower than 7 is acidic, with 1 being the most acidic and 6 the least acidic. A solution with a pH higher than 7 is basic, with 8 being the least basic and 13 being the most basic.

Air enters through the nose (and sometimes the mouth), moves through the nasal cavity, the  pharynx, the  larynx, enters the  trachea, moves through the  bronchi  andbronchioles  till the alveoli.

4) repetitive change