Question: However, no trace remains of their original fortifications.
The fortifications are thought to not exist as there are no traces.

Answer: it is not possible to tell

Question: Following the death of the Prophet Mohammed in 632, Arab armies, united under Islam, poured out of their homeland, and soon took Egypt, Syria, and Palestine from the Byzantines; Constantinople was besieged from 674 to 678, but survived because of its defences.
Constantinople fell to the Arab armies after a one-month siege.

Answer: no

Question: A direct loan financing account may hold uninvested balances to bridge transactions that are integral to its operations, such as when it borrows from Treasury to disburse direct loans prior to the time of disbursement; it earns interest on these balances to reflect the time value of money and thereby finance the interest it pays on its debt to Treasury.
The treasury has many debts.

Answer:
it is not possible to tell