The first answer is- The reason why the Indus Valley Civilization vanished is still unknown. Not many artifacts have been found to let us gain insight into their culture. Their writing was also mostly in Sanskrit, which no one can translate in this day and age.
The 2 answer is ----- Best Answer: Their great architectures and their systems also most of the houses had toilets in them which was uncommon at the time
The answer is A.
The feudal system would follow from the king down to the serfs.
What is confusing is the lords vs. knights. Lords will rule over knights and knights will rule over serfs.
Meaning the system kind of looks something like this:
King
Lord — Lord — Lord
Knight — Knight — Knight — Knight — Knight — Knight
And serfs
Hope this helps, have a great day!