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.
The Answer is C Gas exchange take place in our lungs
Answer:
- Human growth and functioning can be explained by the functioning of the cells.
- Cells are the fundamental units of humans.
- The functioning of the cells in the body determine human health.
Explanation:
The cell is the basic unit of life. Therefore the biochemical activities of the cell at a micro-level will definitely influence overall physiology at the macro level of an organism. For example, the production of Thyroid hormone at the molecular level by the cells in the thyroid glands will influence the metabolisms of all cells in a human being and therefore affect the organism’s overall growth and development.
<span>Lysosomes are organelles which are responsible for breaking down and digesting wastes in the cell.
Lysosomes and vacuoles have the same functions. Both are enclosed organelle compartments within a cell and are recycling centers responsible for breaking down substances or complex molecules that goes into a cell. Both are sacs which contain digestive enzymes for breaking down foreign materials, food, and pathogens. Vacuoles are found in plant cells and lysosomes are in animal cells. Vacuoles play an important role in plant’s food production. It stores water and hydration of plants.<span>
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