Which of the following ph values indicates a solution with the highest concentration of hydrogen ions

1,2,3,4,5 and 6.

Explanation:

If a solution having pH values such as 1,2,3,4,5 and 6 indicates that the solution has the highest concentration of hydrogen ions because below pH 7 the concentration of hydrogen ions increases and the solution tends to more acidic. Highest concentration of hydrogen ions are present in a solution having pH 1 and when the pH value increases from pH 1, the concentration of hydrogen ions decreases.

but there is no

i guess you forgot putting it.

organ system-an organ system is a group of organs that work together to perform one or more functions. each does a particular job in the body, and is made up of certain tissues.