Which of the following was not a an important invention created at the turn of the 20th century

radio

Explanation:Radio was not an important invention in the early 20th century. Instead it was developed by Heinrich Hertz in the 18th century. The cotton gin (APEX)

the cotton gin

Explanation:

apex

all persons entering into t

he employment of the compan

y, are considered as engaged

for twelve months, and those who leave

sooner, or do not comply with all these

regulations, will not be entitled

to a regular discharge.