a woodpecker nesting in a cavity of a dead tree a tapeworm absorbing food in the digestive tract of a wolf a polar bear hunting a seal for food a hummingbird transferring pollen between flowers
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Which is the best example of a parasitic relationship?
Possibilities:
- a woodpecker nesting in a cavity of a dead tree
- a tapeworm absorbing food in the digestive tract of a wolf
- a polar bear hunting a seal for food
- a hummingbird transferring pollen between flowers

a tapeworm absorbing food in the digestive tract of a wolf