Two that I know of are a sextant, and maybe an astrolabe
C. Convergent
Explanation:
When two plate boundaries collide, it causes earthquakes. The deepest and most powerful earthquakes occur at plate collision (or subduction) zones at convergent plate boundaries.
You made an account for brainy. That’s your most interesting discovery.
The horizon is always always always always ALWAYS 90˚ above the zenith.
