If mutations arise that affect shell thickness within a snail population, then with crabs present, those mutations:

you're crazy : )

b. safety skills, for handling tools and food products, and honesty, for following rules and regulations

explanation:

you do not need teaching skills if you work at a processing factory. you also don't need accuracy for closely inspecting equipment and operating heavy machinery safely if you are working at a processing factory. and lastly, you don't need accuracy for monitoring animals, and patience and determination, for observing and caring for animals. if you work at a processing factory, you don't need to care for animals.

natural resource systems. - third choice