Question

each thin filament consists of:
a a double strand of myosin molecules
b a rod - shaped structure with \heads\ projecting from each end
c chains of myosin molecules
d six molecules coiled into a helical structure
e two actin protein strands coiled helically around each other

Explanation:

Thin filaments in muscle fibers are mainly composed of two actin protein strands that are coiled helically around each other. Myosin is part of thick filaments (so options A, C are wrong). Option B describes myosin structure more. Option D is not the correct composition description for thin filaments.

Answer:

E. two actin protein strands coiled helically around each other