Biology · ANIMAL KINGDOM

Cyclostomes exhibit a unique life cycle involving spawning migration. Which statement regarding their habitat, spawning, and larval lifecycle is correct?

1. They are freshwater organisms that migrate to the sea for spawning, where adult larvae develop
2. They are marine organisms that migrate to fresh water for spawning, die after spawning, and their larvae return to the ocean after metamorphosis
3. They are marine throughout their life cycle and lay eggs directly in deep oceanic trenches
4. They reproduce by asexual budding in estuarine waters and lack a larval stage