Hydrogen peroxide production by select species has been shown to play a role in ______ between species within biofilms.

• A. Spatial organization
• B. Nutrient sharing
• C. pH neutralization
• D. Genetic exchange

Answer: (A)

Hydrogen peroxide production by certain microbes acts as a diffusible antimicrobial that creates chemical boundaries within a biofilm. As H2O2 is released, it diffuses through the extracellular matrix and imposes oxidative stress on neighboring, susceptible species. This selective pressure establishes gradients and zones where only tolerant or resistant organisms can thrive, leading to a distinct spatial pattern or architecture in the biofilm. Over time, these interactions promote organized, layered communities rather than a random mix of species. This is about how chemical clashes shape who sits where, not about sharing nutrients, neutralizing pH, or exchanging genes.