Which of the following is NOT a sign of pest activity?

Unopened food containers indicate that the food inside has not been tampered with or compromised, making them less likely to show signs of pest activity. In contrast, signs like grease marks, holes or gnaw marks on packaging, and feces or droppings in hidden areas are clear indicators of pest presence. Grease marks can suggest frequent activity along particular paths used by pests, while holes or gnaw marks are direct evidence of pests attempting to access food. Droppings found in hidden areas suggest an established pest presence. Therefore, unopened food containers serve as a safeguard and do not display any evidence of pest activity, making them an irrelevant factor in this context.