Answer:
Through seafloor spreading.
Step-by-step explanation:
Subduction balances the formation of new oceanic crust at divergent boundaries by the formation of new oceanic crust through seafloor spreading. The oceanic crust sinks into the mantle which creases an empty space that can be filled with magma that is responsible for the production of new crust on that empty space of subduction zone so we can conclude from this discussion that formation of new crust balances at divergent boundaries through seafloor spreading.