Eli Whitney’s development of interchangeable parts led Frederick Taylor to propose a system of

Taylor system or Taylorism developed a widely used system to make industrial production more efficient.

Explanation: I hope this helps :)

the  seven  days  battles  were  a series of seven battles over seven  days from june 25 to july 1, 1862, near richmond, virginia,  during  the american civil war. the  seven  days ended with mcclellan's army in relative safety next to the james river, having suffered almost 16,000 casualtiesduring  the retreat.