Cells communicate through their own language of chemical signals. Different compounds, such as hormones and neurotransmitters, act like words and phrases, telling a cell about the environment around it or communicating messages.
Answer:
The Z lines and H- zone shortens during the muscle contraction.
Explanation:
Sarcomere is the area between the two Z lines. The Z- lines are present in the centre of I - band and H - zone is present in the A - band. The actin filaments which are thin filaments present in I- band and contracts, slide over the myosin filament during contraction.
The I - band, H- zones are became shortens as they are thin than the A- band. It is anisotropic band having thick myosin filaments. They are not flexible and remain in its constant shape during the muscle contraction.
After the muscle contraction, the A- band and the H- zone comes to their original shape. In other words, the sarcomere shortens and comes back during muscle contraction, and relaxation.
Lysosomes are organelles that float on the cytoplasm and their main function is to secrete waste out of the cell and digest.
Lysosomes are found in eukaryotic cells and yes, they are present in plant cells.
Hope it helped.
BioTeacher101