Answer:
I'm pretty sure the answer is A
Acetylcholine..
hope it helps
1. Both processes release energy
2. Both start with the breakdown of a nutrient (glucose)
3. Both yield byproducts
4. Both take place in a cell
5. Both involve pyruvate (pyruvic acid
This is a physics question, not biology, but...
f=1/T where f is frequency and T is the period.
f= 1/(1/3)=3
frequency =3 Hz