Very easy
which of these had the biggest impact on industrialization in the early 1800s?
a) the cotton gin
b) the transistor
c) interchangeable parts
d) internal combustion engine

Interchangeable parts are components that are, for practical purposes, identical. The concept of interchangeability was crucial to the introduction of the assembly line at the beginning of the 20th century, and has become an important element of some modern manufacturing but is missing from other important industries. 

The  pan-african movement  was an "emotional, cultural, psychological and ideological  movement  that began among the  african  dispora in the western hemisphere, for a closer  purpose, so that  african  people could feel secure, attain political, economic as well as psychological power visa vis other races or world regions" .