Answer:
The correct answers are option 2, 4 and 6
Explanation:
2-The T tubules are the extensions of the cell membrane that goes deep into the center of the middle of the skeletal and cardiac muscles and are in close contact with the sarcoplasmic reticulum.
These tubes plays 2 vital functions in connecting an action potential to muscle contraction. T tubules causes the action potential from the plasma membrane into the interior of the muscle cell through voltage-gated Na+ and K+ channels.
An action potential causes the opening and closing of Calcium channels in the sarcoplasmic reticulum. The resulting change in cytosolic Ca2+ concentration triggers contraction of the myofibrils.
The T tubules play two important roles in linking an action potential to muscle contraction.
That certain image, whatever it may be would have been magnified a total of 40 times. In order to find that answer, all you have to do is divide 50mm by 1.25mm and you will end out with 40mm at the end.
The answer is C. nitrogen.
Plants are main producers in ecosystems so, primary productivity of ecosystems depends on them. Carbon is necessary for plants, but it is widely present in plants. On the other hand, calcium and sodium are not as essential. However, nitrogen is important for plants because it is necessary to make proteins. Proteins take part in many different processes such as photosynthesis (this is actually primary productivity). But, nitrogen is not available to plants, they cannot absorb it simply from the air but rely on some symbiotic bacteria which are able to.
Understandable, have a great day