Study the given diagram of a simple stirred tank bioreactor. The part labelled X helps in adding buffers to the culture medium. Which of the following conditions does it help to control?
![Cell Therapy Horizontal Stirred Tank Bioreactor - China Fermenter, Single Use Bioreactor | Made-in-China.com Cell Therapy Horizontal Stirred Tank Bioreactor - China Fermenter, Single Use Bioreactor | Made-in-China.com](https://image.made-in-china.com/202f0j00SNyiRTHlsEzt/Cell-Therapy-Horizontal-Stirred-Tank-Bioreactor.webp)
Cell Therapy Horizontal Stirred Tank Bioreactor - China Fermenter, Single Use Bioreactor | Made-in-China.com
![Design and Performance of Single-Use, Stirred-Tank Bioreactors - BioProcess InternationalBioProcess International Design and Performance of Single-Use, Stirred-Tank Bioreactors - BioProcess InternationalBioProcess International](https://bioprocessintl.com/wp-content/uploads/2016/11/14-10-sup-Nienow-F2b.jpg)
Design and Performance of Single-Use, Stirred-Tank Bioreactors - BioProcess InternationalBioProcess International
![A schematic diagram of a stirred tank bioreactor. Adopted from NCBC 22 | Download Scientific Diagram A schematic diagram of a stirred tank bioreactor. Adopted from NCBC 22 | Download Scientific Diagram](https://www.researchgate.net/publication/250223909/figure/fig4/AS:392822578741284@1470667609600/A-schematic-diagram-of-a-stirred-tank-bioreactor-Adopted-from-NCBC-22.png)
A schematic diagram of a stirred tank bioreactor. Adopted from NCBC 22 | Download Scientific Diagram
![Design and Performance of Single-Use, Stirred-Tank Bioreactors - BioProcess InternationalBioProcess International Design and Performance of Single-Use, Stirred-Tank Bioreactors - BioProcess InternationalBioProcess International](https://bioprocessintl.com/wp-content/uploads/2016/11/14-10-sup-Nienow-F2.jpg)