Question

two populations of annelids (worms) live in distinct areas and on different soil types. researchers are interested in whether the populations have acquired different types of reproductive isolation. which method would be best to determine whether two populations exhibited temporal isolation?
move them into a common experimental setting to see whether they will produce offspring. if they produce few offspring, they exhibit gametic isolation.
move them into a common experimental setting to see whether they will produce offspring. if they produce many offspring, they exhibit gametic isolation.
observe when each population is active. if they are active at different times, then they exhibit temporal isolation.
bring them into the lab. observe single pairs of a male from one population and a female from the other. see whether the sperm from the males of one population will fertilize eggs of the females of the other. if they do not, then they exhibit gametic isolation.
bring them into the lab. observe single pairs of a male from one population and a female from the other. see whether the sperm from the males of one population will fertilize eggs of the females of the other. if they do, then they exhibit gametic isolation.

Explanation:

Temporal isolation is based on differences in activity or breeding times. Observing when each population is active can determine if they are active at different times, which indicates temporal isolation. The other options pertain to gametic isolation - the ability of gametes to fuse.

Answer:

Observe when each population is active. If they are active at different times, then they exhibit temporal isolation.