2- Thin myofilament: A. Is made of type II myosin. B. Is made of desmin. C. Is made of tropomyosin. D. Is made of actin G. E. Is limited by two striations Z. F. Is made of caldesmone G. Is made of calpontine H. ,Is found only at the level of the light band <<I>> I. Is found only at the level of the dark band « I »

The thin myofilament in muscle cells:

A. Is not made of type II myosin. Type II myosin forms the thick filaments in muscle cells.

B. Is not made of desmin. Desmin is an intermediate filament protein found in muscle cells, but it is not a component of the thin filaments.

C. Is made of tropomyosin. Tropomyosin is a protein that winds around the groove of the actin filament in muscle cells.

D. Is made of actin G. Actin G (globular actin) polymerizes to form F (filamentous) actin, which is a major component of the thin filament.

E. Is limited by two striations Z. The Z lines define the boundaries of a single sarcomere in a muscle cell, and the thin filaments are anchored to the Z lines.

F. Can be associated with caldesmon. Caldesmon is a protein that can bind to actin, tropomyosin, and calmodulin in smooth muscle cells, potentially affecting the function of the thin filaments.

G. Is not made of calpontin. Calponin is a protein found in smooth muscle cells that can bind to actin, tropomyosin, and calmodulin, potentially affecting the function of the thin filaments.

H. Is found at the level of the light band "I". The I band in a sarcomere is the region that contains only thin filaments.

I. Is not found only at the level of the dark band "A". The A band in a sarcomere is the region where thick and thin filaments overlap.