Please answer the following question: Zebina robustior -  Zebina robustior is a species of minute sea snail a marine gastropod mollusk or micromollusk in the family Rissoinidae. Given a choice of categories company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work, the text refers to which one?
Answer:
Animal