Question

read the text.
you have probably heard of the ph scale, which measures how acidic or basic different solutions are. a solutions acidity or basicity is related to its concentrations of hydronium ions and hydroxide ions. when a strong acid is added to a solution, atoms in the solution break apart to form hydronium ions. this leads to a more acidic solution. when a strong base is added to a solution, atoms in the solution break apart to form hydroxide ions. this results in a more basic solution.
match causes with their effects.
the solution becomes more basic. the solution becomes more acidic.
cause effect
hydronium ions form in the solution.
hydroxide ions form in the solution.

Explanation:

The text states that when hydronium ions form (from adding a strong acid), the solution becomes more acidic. When hydroxide ions form (from adding a strong base), the solution becomes more basic.

Answer:

Hydronium ions form in the solution. → The solution becomes more acidic.
Hydroxide ions form in the solution. → The solution becomes more basic.