What is a common characteristic of halophiles?

Halophiles are organisms that have adapted to thrive in environments with high salt concentrations, such as salt lakes, saline soils, and salt mines. This ability is a defining characteristic of halophiles as they possess specialized mechanisms to manage osmotic pressure and maintain cellular function in such hypertonic conditions. They often have unique cell structures and biochemical pathways that enable them to stabilize proteins and cellular processes against the stress caused by high salinity.

In contrast, the other options refer to characteristics that are not associated with halophiles. For instance, the requirement for high temperatures is more typical of thermophiles, organisms that thrive in extremely hot environments. The mention of low-oxygen environments pertains to anaerobes, which may thrive in conditions lacking oxygen but do not specifically relate to salt tolerance. Sensitivity to pH changes does not define halophiles specifically, as organisms across various environments can be sensitive to pH levels, but halophiles themselves are primarily defined by their salt tolerance.