Answer:
1) True
Explanation:
Cells of Sinoatrial (SA) node make up the auto rhythmic cells of heart as in normal physiological conditions , SA-node is responsible to set the pace of the rest of the heart (pacemaker) at a rate of 70 to 80 beats per minute.
The cells of SA node has the ability to self-excite thus able to generate action potential without external stimulation by nerve cells. Thus they initiate the cardiac cycle providing the conduction system.
Hence the statement , SA nodal cells are unique in that they exhibit autorhythmicity, meaning they are capable of depolarizing and firing an action potential spontaneously without any external influence, is true.
<span>organelle, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystem, and biosphere. These have been arranged from the smallest to the largest. The biosphere is the largest level of organization while the organelle is the smallest. However, the basic form of life begins with the cell. Many cells together form a tissue and several tissue form an organ.
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Part 1: The eclipse observed was a lunar eclipse. The sun is usually not visible during these eclipses. The moon is new during a solar, but full during a lunar. It is red during a lunar eclipse due to a reflection of the Suns light behind earth. It happens more often because Earths shadow is larger than the moons. The umbra is larger as well, so it lasts longer than a solar eclipse.
Part 2: The moon is in the full moon phase. The Earth is in between the Moon and the Sun. The umbra of Earths shadow is cast directly on the moon, casting out the suns light. A tint of the reddish color shines around earth from the Sun making the dark moon appear red. The moons axis is slightly tilted , so the umbra does not hit the moon every month. But when it does? It creates a lunar eclipse.
Plasma membrane which is also the cell membrane
