As a result of the system of mass production, the majority of factory owners
replaced skilled workers with unskilled workers.
eliminated women workers and hired only male workers.
used only child laborers.
replaced unskilled workers with skilled workers.

replaced skilled workers with unskilled workers.

Explanation:

The majority of factor owners did not need skilled workers anymore since all they needed was people able to work on assembly lines or operating the machines. By hiring unskilled workers, they could pay less for the work that they needed.

replaced skilled workers with unskilled workers.

Explanation:

The majority of factor owners did not need skilled workers anymore since all they needed was people able to work on assembly lines or operating the machines. By hiring unskilled workers, they could pay less for the work that they needed.

The answer is: They replaced skilled workers with unskilled workers.

The answer is: They replaced skilled workers with unskilled workers.

the answer here would be

it allows shippers to carry commercial goods, which allows them to save time and money.