Answer:
The correct answer will be option-C
Explanation:
The rhythm of the heartbeat is controlled by the pacemaker of the heart called the sino-atrial node.
The SA node generates action potentials which trigger the contraction and relaxation of the atrium and ventricles. The membrane potential generation initiates by the depolarization of the cell membrane when the L type of Ca⁺² ions opens up and calcium ions enter the cell.
This depolarizes the cell until the potential threshold is reached which lies between the -40 and -30 mV.
Thus, Option-C is the correct answer.
Answer:
ameoba
Explanation:
ameobas are single celled organisims
Answer:
See explanation
Explanation:
Fossil records contain an extensive detail of the evolution of various species on earth which have been preserved in the remains of these organisms or imprints that organisms that existed long ago must have left in sedimentary rocks.
Fossil records basically tell us about the past. They tell us about the species that once existed on earth. They also tell us how long these species existed and how the were related to other species.
This information help us to work out how these organisms lived and the environment where they lived.
I believe the answer might be A
