Answer:
The preferable options will be -
T-tubule system
Explanation:
- T-tubules or transverse tubules are a part of the skeletal and cardiac muscle membrane systems. They are the cell membrane extensions that can penetrate into the center of those muscles.
- It contains a large amount of on channels, transporters, and pumps. It allows the transmission of the action potential, frequently. T-tubules also regulates the cellular calcium concentration.
Since it has 4 protons, it must have an atomic number of 4. (That makes it beryllium.)
Since it has a 4 protons and 5 neutrons, it has a mass number of 9.
The second one because they can indicate infection and sickness
