What were the reasons for the decline of the ancient Roman Empire?

The reasons for the decline of the ancient Roman Empire were following:

1. The Institution of Slavery — Slaves who had no interest in the development or preservation of the empire constituted three quarters of the subjects of Rome by the third century CE.
2. Decline in population — Due to constant wars, avoidance and postponement of marriage, infanticide and plagues, the Roman population declined considerably and non-romans mainly barbarians flooded the empire.
3. The Land — It was the monopoly of a few wealthy persons.
4. Heavy taxes — People were heavily taxed to provide for extravagant court and the maintenance of a huge army and government officials. But only one-third of the revenue reached the imperial treasury as the remaining two-third was pocketed by the provincial officers.
5. Wide gap between the rich and poor — The rich lived in luxury whereas poor lived in great poverty. The poor did not take any interest in the affairs of the state when enemies attacked their territory.
6. No discipline in the army — There was neither loyalty nor discipline in the army. The army at times became too strong and army commanders put on the throne weak rulers, many of whom were removed from the throne in tragic circumstances.
7. Decline in production — Agricultural and industrial production declined due to numerous wars and revolts.