Final answer:
The signs of pests can include various indicators such as open sacks of grains with spillage, dead carcasses, and traps that are untouched. However, bits of paper and cardboard that might be used for nesting are not typical signs of pests.
Step-by-step explanation:
The signs of pests include sacks of grains with corners or seams open and spillage, dead carcasses on shelving, on the floor, and on stored food packaging, traps that have not been tripped or bait that has not been eaten, and bits of paper and cardboard that might be used for nesting.