Answer:
Seismographs, shipbuilding methods, and paper made from wood pulp
Step-by-step explanation:
Zhang Heng, a Han scientist, developed the earliest known seismograph to detect and measure earthquakes. Cai Lun, an official in the Han court, invented a method for making paper out of wood pulp, and the Chinese made advances in methods of shipbuilding and invented the rudder to steer.