question: How many openings do adult tunicates have that siphon water in and out of the body?
distractor3: one
distractor1: three
distractor2: four
correct_answer: two
support: Adult tunicates are barrel-shaped. They have two openings that siphon water into and out of the body. The flow of water provides food for filter feeding. Tunicates reproduce sexually. Each individual produces both male and female gametes. However, they avoid self-fertilization. Tunicates can also reproduce asexually by budding.