Question

question 4 of 10
which of the following was not an important invention of the early 20th
century?

a. the airplane

b. the cotton gin

c. the phonograph

d. the electric lightbulb

Explanation:

To solve this, we analyze the invention timelines:

• The airplane (A) was invented in 1903 (early 20th century).
• The cotton gin (B) was invented by Eli Whitney in 1793 (late 18th century, not early 20th).
• The phonograph (C) was invented in 1877, but significant developments were in the early 20th century.
• The electric lightbulb (D) had key developments in the late 19th/early 20th century.

Answer:

B. The cotton gin