🔍 Key Concepts

• Microbial contamination in fuel and what it typically looks like • How corrosion and pitting relate to biological activity in fuel tanks • Typical color/appearance of sludge, slime, or growths caused by microbes

💭 Think About

• For each option, ask yourself: Would microbes living in fuel and water cause this effect on metals or surfaces? • Think about the usual colors and textures of microbial growth in fuel tanks and sumps. • Consider which option describes a condition that actually sounds like an improvement in metal appearance rather than damage or fouling.

✅ Before You Answer

• Identify which three options describe damage or fouling associated with contamination. • Identify if any choice describes a cleaning or polishing effect instead of contamination. • Before deciding, picture what you would realistically see inside a contaminated fuel tank versus a clean one.