True statement about smooth muscles
Smooth muscle

No T tubules. Instead it has Caveolae which is invagination of smooth muscle membrane, it has voltage gates L-type Ca2+ channel
No troponin Ca2+ binds Calmodulin
No Z lines. Achorage for actin filaments is provided by dense bodies.
Presence of Caveolae
Ca2+ binds to troponin C
The anchorage for actin filaments is given by Z-lines
Voltage gates L-type Ca2+ channel are present in T-tubules