The correct answer to this open question is the following.
Although there are no options attached we can say the following.
Rene Descartes believed in "animal spirits" that moved through your muscles. This was an early concept of what body system?
Answer: This was an early concept of the nervous system.
Descartes put it this way. That from the Pineal Gland, there were nerves, hollow tubes with "animal spirits" that crossed the small fibers of the body that connected the sense organs with the brain. The stimulation of these sense organs produced motion in the body.
Descartes was the French philosopher that was also renowned for his philosophical approaches to the "truth."
According to Descartes, the responsibility for finding out the truth was oneself and the mind when it states "I think therefore I am." French philosopher, Rene Descartes's approach to the truth had to first, express doubt.
Those responsible for finding the truth were supposed to complete this task by doubting first, questioning their own existence. Then, through the mind, the reason, confirm their existence because they could think.
