Final answer:
The statement "The actions of Charles I contributed the most to English royal power being on a downward spiral between 1510 and 1688." is true. This led to the English Civil War, his execution, and culminating in the Glorious Revolution which limited monarchical power and bolstered parliamentary authority.
Step-by-step explanation:
The statement that the actions of Charles I contributed the most to English royal power being on a downward spiral between 1510 and 1688 is largely true.
During his reign, Charles I's policies and actions aggravated tensions between the monarchy and various societal groups, leading to the English Civil War and his eventual execution.
He dismissed Parliament and attempted to rule without it, leading to fiscal chaos and heightened divisions.
The civil wars of the 1640s and later the Glorious Revolution in 1688 were critical events that significantly diminished the power of the English monarchy and increased parliamentary sovereignty.
This sequence of events constituted a major shift in English governance and ultimately restricted royal authority.
Hence, the statement is true.