Explanation: When human learned how to control fire it was a very important step for their culture. fire helped the homo erectus to get warmth during the winter time and cook food.
Before fire hominid used to eat raw vegetables and flesh. The exact time when the fire was invented is not known but it took place approximately 230,000 years ago.
The evidences that show that homo used fire for the first time is almost 400,000 years ago.
An independent variable is the variable you think is the cause,while a dependent variable is the effect. you manipulate the independent variable and measure the outcome in the dependent variable.
