The answer is: Pre operational stages.
According to piaget's theory, children will started to recognize and learn to manipulate symbols during pre operational stages.
They will start to understand hand gestures, facial expression, and voice intonation that given by other people.
To maximize the outcome as well to minimize the production cost
In the early twentieth century A.Henry Ford developed a form of modern assembly line.
Explanation
The modern Assembly Line is a form of modern assembly and production which was used for the production of the Ford T model. This assembly line system is based on the concept of allocation of specific task to different workers who are organized in a line or chain formed by the station in which the worker performs its task
The major difference between anabolic drugs and other illegal drugs is the fact that anabolic drugs do not cause intoxication. Anabolic drugs, which were first manufactured in the 1930s, are now prescribed for various beneficial purposes such as the stimulation of growth and appetite, treatment of cancer, treatment of AIDS and the induction of male puberty. Persistent use of anabolic drugs for a prolonged period, however, carries great health risks.
Steel is better in building because steel is more durable than wood when properly treated
