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.
Water purification is the process of removing undesirable chemicals, biological contaminants, suspended solids, and gases from water. The goal is to produce water fit for specific purposes.
emotional comfort. according to some studies in psychological science, chicken soup is good for your emotions. the soup plays a great role in reducing the irritation that accompanies common cold. it emotionally and psychologically makes an individual to feel better. in fact individuals are encourage to over eat chicken noodle in the duration they suffer from the common cold.
Stem
1. Grows upward show negative gravitrotropism
2. Stems don't absorb water and nutrients
3.Stems have trichomes
Roots
1 show positive gravitrotropism
2 absorb water and Minerals
3 bears root hairs
