Box jellyfish have sophisticated eyes with a lens and a retina. How big is its brain?

about the size of a peanut
about the size of a wallnut
about the size of a coconut
jellyfish have no brain
Their speed and vision leads some researchers to believe that box jellyfish actively hunt their prey. Since they have no brain, the mechanisms that could make it happen remain unknown.
correct this question
Paul Caspack
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