Assuming there is zero cosmological constant, how do we hope to determine if the Universe will stop expanding?
a. By looking for inhomogeneities at the edge of the observable Universe.
b. By measuring the number of galaxies within the Local Group.
c. By comparing the ages of globular clusters to the ages of galaxy clusters.
d. By determining if the average density of the Universe is greater than the critical density,
e. By determining precisely the epoch of recombination.