Several conditions can affect bacterial growth, including: 1. Temperature: Bacteria have optimal temperature ranges; extreme heat or cold can inhibit growth. 2. pH: Most bacteria prefer neutral pH (7), but some thrive in acidic or alkaline conditions. 3. Oxygen availability: Some bacteria are aerobic, others are anaerobic, and some are facultative (can grow in both conditions). 4. Nutrient availability: Essential nutrients like carbon, nitrogen, and minerals are necessary for growth. 5. Salinity: High salt concentrations can inhibit bacterial growth, though some bacteria are adapted to saline environments.