What are the answer choices?
Yes it does, they are everywhere
I believe its large blue vessel also known as vena cava
Answer: CHANNEL PROTEINS provide openings in the plasma membrane for substances to flow through without changing structure, and CARRIER PROTEINS allow passage of substances through the plasma membrane after undergoing a subtle change in shape.
Explanation: They are described thus:
A channel protein is a protein that allows the transport of specific substances across a cell membrane.
Carrier proteins are proteins that carry substances from one side of a biological membrane to the other. Many carrier proteins are found in a cell’s membrane, though they may also be found in the membranes of internal organelles such as the mitochondria, chloroplasts, nucleolus, and others.
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.
