In which of these behaviors is it critical that members of the same species be able to recognize one another?
a)
migration
b)
hibernation
c)
territoriality
d)
courtship behavior

The behavior which is critical that members of the same species be able to recognize one another is courtship.  
It is a collection of instinctive behaviors which result in mating and eventual reproduction.
Animal courtship may be rather simple which involves a small number of chemical, visual, or auditory stimuli. It may be also be a highly complex series of acts by two or more individuals, using many different modes of communication.

This type of galaxy is an approximately ellipsoidal shape and a smooth, nearly featureless image. they are the largest single star systems, in the universe and are built by the collisions of many smaller galaxies.

D.) domain, kingdom, phylum, class, order, family, genus then species