What is an interesting
facts on deep ocean trenches?

There are sometimes weird creatures there that use chemosynthesis to live (absorbing chemicals from volcanic vents). These are the only life forms we know of that don't rely on the sun's light in any way.

The oceanic trenches are hemispheric-scale long but narrow topographic depressions of the sea floor. They are also the deepest parts of the ocean floor. Oceanic trenches are a distinctive morphological feature of convergent plate boundaries. Along convergent plate boundaries, plates move together at rates that vary from a few mm to over ten cm per year.

Answer primary waves;