Answer:
"Action potential is a rapid rise and subsequent fall in voltage or membrane potential across a cellular membrane with a characteristic pattern."
It is the mode through which a neuron transports electrical signals.
Explanation:
- Option - (a) is the best choice to choose from,
- <u>The refractory period :</u>
A second action potential cannot occur until the membrane has recovered or reestablished, this is the refractory period. The absolute refractory period coincides with inactivation of voltage-gated sodium channels which makes it impossible to generate another nerve impulse.
It sends an impulse back to the cell body of a neuron
The correct answer is an accumulation of microorganisms in deep marine environments.
Chalk rock refers to a pure form of limestone produced in tropical and warm seas about 100 million years ago in the Cretaceous period. The microscopic marine algae known as coccoliths thrived in the ancient seas. Their shells were comprised of calcite. With the death of the algae, their bodies sunk to the floor of the sea and sediment of chalk got deposited.
Over many years layers of chalk sediment got deposited and resulted in compaction of loose sediment into solid chalk rock.
The answer is “Organisms that contain functional recombinant DNA
