A new type of communication system has been discovered that consists of thin, highly elongated tubules capable of conducting cell-surface proteins, cytoplasmic vesicles and calcium signals from one cell to another. This system is referred to as:

A. tunneling nanotubes

B. tunneling nanotypes

C. scanning tunneling EMs

D. sarcoplasmic tubules

E. T tubules

Answer: A. tunneling nanotubes

Explanation:

A tunnelling nanotube (TNT) also called membrane nanotube is a concept that has been applied to protrusions extending from the plasma membrane that enables different animal cells to interact over long distances, often over 100 μm between T cells.

There are two types of tunneling nanotube including one type of smaller than 0.7 micrometres in diameter which contains actin, and carries parts of plasma membrane in both directions between cells. The second type is larger than 0.7 μm that contains both microtubules and actin, and may carry cytoplasm components such as vesicles and organelles, including whole mitochondria, between cells.

TNT functions in the development of various diseases by allowing the movement of protein, pathogens aggregates and mitochondria.

Hence, the correct option is A. tunneling nanotubes.