<span>the radius of the sun is 432,450 miles (696,000 km)</span>
Answer:
In the boreal forest the ground thaws more and does not have a permafrost layer. This allows trees to take root. Compose an argument for categorizing mountains and polar regions as terrestrial biomes. Mountains and polar regions have these characteristics and provide land on which certain plants and animals can live.
Explanation:
Answer:
The source of Calcium (Ca⁺⁺) for the skeletal muscle cells is the sarcoplasmic reticulum, the main store of intracellular Ca⁺⁺.
Explanation:
Calcium (Ca⁺⁺) is an ion that plays an important role in muscle contraction, a process that requires high cytoplasmic concentrations of this ion to promote myofibrillary activity.
The sarcoplasmic reticulum (SR) -equivalent to the endoplasmic smooth reticulum- is an organelle that regulates the contractile activity of skeletal muscle. The two terminal cisterns of the SR attach to the T-tube, forming a triad, which surrounds the myofibrilla.
Once the muscle cell receives the signal to contract, the Ca⁺⁺ channels are opened and allow Ca⁺⁺ to enter the cell, promoting the exit of this cation from the SR and increased its cytoplasmic levels. This stimulates muscle contraction.
The temperature is different. St. Louis is hotter by approximately 10 degrees
