Because we control them both in the same direction so if we where like some lizards that move each eye individually then we would see two images
Answer: a. cervical enlargement.
Explanation:
Cervical enlargement corresponds to the enlargement of the spinal cord. The spinal cord is the origin of the spinal nerves that contribute to an important task of supplying blood to the upper limbs.
The cervical enlargement results in an increase in the volume of the motor cells in the ventral part inside the grey matter. The motor neurons which are sited posteriorly supply to the upper limbs. Those which supply to the distal muscles are situated further posteriorly.
D. Both are sources of energy because Carbohydrates provide the cells for short term energy but lipids store the energy for when it's needed.