Question

the steam engine
the idea of using steam for driving stationary machinery originated in the early centuries. for a long time, no one seemed to have thought of using steam for transportation purposes. in the earlier historical records, there is mention of \heat engines,\ which were used for organ blowing, the turning of spits, and like purposes. but from this early date until the 17th century, practically no progress was made in the use of steam. though men had experimented with steam up to this time with more or less success, the world is chiefly indebted for the developed type of the steam engine to james watt and george stephenson.
james watt, who secured the position as a maker of scientific instruments in the university of glasgow, proposed an idea for improving the existing steam engine, which was used for pumping mines. for a long time, owing to a lack of money, he had difficulty in establishing the merits of his improvements. finally, he formed a partnership with matthew boulton, a wealthy and energetic man who lived at birmingham, england. they began the manufacture of steam engines at birmingham, under the firm name of boulton and watt. this partnership was very successful. watt supplied the inventions; boulton furnished the money and attended to the business.
before the time of watt, the steam engine was exclusively a steam pump—slow and wasteful of fuel. watt made it a quick, powerful, and efficient engine, requiring only a fourth as much fuel as before. under his first patent, the engine was still used only as a steam pump, but his later improvements adapted it for driven stationary machinery of all kinds. the commercial success...
select the correct answer.
which sentence from the passage supports the idea that the “world is chiefly indebted” to james watt and george stephenson for developing the steam engine?
a. before the time of watt, the steam engine was exclusively a steam pump—slow and wasteful of fuel.
b. the first train consisted of thirty - four cars weighing, all told, ninety tons.
c. the idea of using steam for driving stationary machinery originated in the early centuries.
d. watt made it a quick, powerful, and efficient engine, requiring only a fourth as much fuel as before.

Explanation:

The question asks for a sentence supporting that the world owes the developed steam engine to Watt and Stephenson. Option D describes Watt's critical improvements that transformed the steam engine into an efficient, powerful machine, which directly relates to his role in developing the steam engine. The other options do not connect to their contributions to the developed steam engine: Option A describes the pre-Watt steam engine, Option B is unrelated to the two figures, and Option C discusses an early steam concept not tied to their work.

Answer:

D. Watt made it a quick, powerful, and efficient engine, requiring only a fourth as much fuel as before.