The correct answer is gunpowder and abacus.
Why this is correct:
- Gunpowder: The Tang dynasty (618-907 AD) is credited with the early development of gunpowder, which would later have a significant impact on warfare and technology around the world.
- Abacus: The abacus, an important calculating tool, saw its development during the Tang dynasty, contributing to mathematics and commerce by allowing for more efficient calculations.
While silk and paper were also significant contributions, they were more prominently developed prior to the Tang period, especially paper, which was invented during the Han dynasty. The Tang dynasty did contribute to their refinement and spread, but the question specifically targets the distinct innovations during that period.