The most important invention of the late 1900s and why?

the escalator

Explanation:

because it allowed people who where tired from walking to rest while they were going up the steps

There's a lot. here are some examples:

Explanation:

1901 : Vacuum cleaner.

1902 : Air conditioning; automated tea maker.

1903 : Electrocardiogram; first powered flight.

1904 : Radar; tea bags; diodes.

1905 : Plastic; windscreen wipers; silencer for guns.

1906 : Radio broadcasting.

1907 : Electric washing machine.

while it was true that the cotton gin reduced the labor of removing seeds, it did not reduce the need for slaves to grow and pick the cotton.

explanation:

before eli whitney's invention of the cotton gin, picking and cleaning cotton was a slow, labor-intensive job. workers, usually slaves, had to pick the seeds from the cotton fibers by hand. this invention made it possible to grow large amounts of cotton on big farms and make money.

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