Question

select the word that means improved something by making small changes. you may have heard that thomas edison invented the light bulb. thats not really true. others had developed bulbs; starting more than seventy years before edison began his work. but edison refined the design of the light bulb in important ways. he was the first to make a light bulb that would last long enough to be practical.

Explanation:

The text gives an example of Thomas Edison who made important small - scale changes to the light - bulb design to improve it. The word "refined" means to improve something by making small changes.

Answer:

refined