Answer:
Option B: Molecule 2
Step-by-step explanation:
'Equilibrium of a molecule inside and outside a cell' means that there are similar numbers of that molecule on the inside and the outside. (hence 'equilibrium')
The number of each molecule is as follows:
Molecule 1 - Inside: 3, Outside: 5
Molecule 2 - Inside: 2, Outside: 3
Molecule 3 - Inside: 1, Outside: 5
Molecule 4 - Inside: 7, Outside: 4
Therefore the correct option is option b. 2
This is because the number of molecules inside the cell and outside the cell are the closest together, most similar out of all the molecules.
Hope this helped!