Answer - Bicycle
Reasoning - It has mechanical components for your body to work and do activity with in the lower part of the body.
This has been answered before in the community. Just re-entering the answer
Answer:
years
Explanation:
Given-
Half life of 
C 
years
As we know -
Where
Mass of radioactive carbon after a time period "t"
initial mass of radioactive carbon
radioactive decay constant
time
First we will find the value of "k"
On solving, we get -
Now, when mass of 14C becomes 
% of the plant material on earth today, then its age would be
years
The answer is generation and propagation of action potential.
Na+ channels are important for generation and propagation of action potential. In normal neurons, when neurons hit threshold and action potential is triggered, the Na+ channels open and Na+ ions enter the neuron. After the depolarization of membrane, Na+ channels inactivate. Thus, w<span>ithout Na+ channels, neurons would not be able to depolarize and consequently, the action potential would not be generated.
</span>
