Question

___________________________________________
Shortens, Lengthens, No change
___________________________________________

During During
Contraction Relaxation
1. Sarcomere
2. A band.
3. I band
4. H band
5. Z band​

Answer 1

Answer:

Sarcomere - During contraction; shortens and during relaxation; no change (i.e. comes back to the original length).

A- band - No change is observed during contraction or relaxation as it literally means the length of myosin fibers.

I- band - During contraction shortens and during relaxation no change (i.e. comes back to its original length; if extended further that is like a pinch in the skin then will lengthen.)

H- zone - Shortens during contraction and no change during relaxation: that

is will come back to its original length which was at the beginning.

Z-line - Like the name suggests is a line so during contraction or relaxation will show no change though the gap between two z-lines will change.

*If lengthens in the question means lengthening after contraction to its original length then, Sarcomere, I-band, H-band will lengthen during relaxation.