Answer:
The cells survive best under acidic conditions
Step-by-step explanation:
To understand this graph, you first need to understand what data is being given. All you are given is cell survival and pH.
With this, the pH has an obvious effect on cell survival. Higher pH (basic environment) correlates to more cells dying. Knowing this, you can rationalize that the more acidic environments with a low pH are the best environment for it.
Also, it would not survive well in distilled water since its pH lies somewhere north of 6, which is shown to not be ideal here.