Fact 1: Organisms cluster around hydrothermal vents in the ocean floor.

Fact 2: To survive, some organisms living near hydrothermal vents have formed close associations.

Given the two facts above, answer the question "How is survival ensured around hydrothermal vents?" with the following options: 
- heat produced
 - Eating a lot
 - Reproducing quickly
 - biological diversity
 - vegetation
 - Being in a cluster
 - Staying far apart
 - hydrate their cells


 

      Being in a cluster   