Similar to the other types of muscle, smooth muscle contraction is caused by the sliding of myosin and actin filaments over each other. Calcium initiates contractions in a different way in a smooth muscle than in a skeletal muscle.
Smooth muscles use less energy to generate the given amount of force, can substain contractile force without fatigue & uses calcium from the sarcoplasic reticulum & extracellular space.
<span>The grasslands typically lie in the middle of large lanmasses, or the interior of continents, where rivers are most likely to flow far away from seawater sources. Here the ever
present value of water can be seen, as it supplies the source of life to all the plants and animals in the ecosystem in a lush and relatively cushy environment when compared to
the biomes like the desert or savannah.</span>
D. They both help organisms to move.
I believe the answer is B. Hope I help! Sorry if not. ):)
