What are the I Bands in Skeletal Muscles Composed Of

Question

What are the I bands in skeletal muscles composed of?
A) discs to which thick filaments are anchored
B) thick filaments but no thin filaments
C) thin filaments but no thick filaments
D) stacked, thick filaments along with parts of thin filaments that overlap both ends

Accepted Answer

I bands in skeletal muscles are composed of thin filaments but no thick filaments. These bands appear lighter under a microscope and decrease in size during muscle contraction.