Because you cannot test it or observe it.
A scientific theory are created through the scientific method, in the scientific method you need to be able observe it and experiment.
Answer: Where would the blood come from if there were a blockage just posterior to the middle cerebral artery on the left? If blood could not get to the middle cerebral artery through the posterior circulation, the blood would flow around the circle of Willis to reach that artery from an anterior vessel.
Explanation:
Answer:
The correct answer is glands.
Explanation:
It is known that brain monitors movement, therefore, one can definitely correlate movement of muscles with the brain that comprises the role of sensory and motor neurons. When a stimulus is obtained by the sensory organs, it is transmitted by the sensory neuron to the brain and from their information is further conducted to the effector organs like muscles by the motor neuron. The glands are the group of cells, which takes part in the secretions when instigated by any particular hormone.