Please answer the following question: Fact 1: Bivalves feed on plankton and nonliving organic matter.  Fact 2: Bivalved arthropods are especially common.  Given the two facts above, answer the question "what do arthropods feed on?" with the following options:  - spiders  - rocks  - seeds  - water  - pollen  - plankton  - barnacles  - food
Answer: