1. economic decline in the romani empire was greatly advanced by what?

The Fall of the Western Roman Empire (also called Fall of the Roman Empire or Fall of Rome) was the process of decline in the Western Roman Empire in which it failed to enforce its rule, and its vast territory was divided into several successor polities. The Roman Empire lost the strengths that had allowed it to exercise effective control; modern historians mention factors including the effectiveness and numbers of the army, the health and numbers of the Roman population, the strength of the economy, the competence of the Emperor, the religious changes of the period, and the efficiency of the civil administration. Increasing pressure from "barbarians" outside Roman culture also contributed greatly to the collapse. The reasons for the collapse are major subjects of the historiography of the ancient world and they inform much modern discourse on state failure.

This is some information i gathered hope this helps! (Had the same question)

productive most commonly means: achieving or producing a significant amount or result.

explanation:

productive can also mean:

producing or giving rise torelating to or engaged in the production of goods, crops, or other commodities.

these depend on how the word productive is used. most likely productive will mean   achieving or producing a significant amount or result.