Dr. garvey measured the ph inside a bacteria cell and found the ph was a level 4. she then injected enough acid into the cell to change the ph to a level 2. she re-measured the ph after several moments and found the bacteria cell remained at ph of 4. what is the most likely explanation?

a. the bacteria cell contained enzymes which changed the ph
b. she made a mistake and injected the wrong acid
c. the bacteria cell contained sugars which increased the ph
d. the bacteria cell contained buffers which regulated the ph

Which statements best describe the differences or similarities between a comparative investigation and an experimental investigation? check all that apply. experimental investigations are best for showing cause-and-effect relationships, while comparative investigations do not necessarily show this type of relationship. comparative investigations are often impractical and unrealistic, while experimental investigations are the most practical and realistic kinds of investigations. comparative investigations allow for the use of a wide range of variables but do not have a control group, while experimental investigations involve variables that can be controlled. both experimental investigations and comparative investigations are designed to answer scientific questions. both experimental investigations and comparative investigations focus on making observations rather than collecting new data.