Which of the following is a common characteristic of all Tarsiiformes?

The common characteristic of all Tarsiiformes is their large eyes, which are adaptations for nocturnal living. Tarsiiformes, commonly known as tarsiers, are small primates that are primarily active at night. The large size of their eyes relative to their body helps them to capture more light in low-light conditions, which enhances their ability to see in the dark and aids in their hunting and foraging for insects and small vertebrates during nighttime.

While flat-nosed structures, diurnal activity patterns, and prehensile tails may apply to different groups of primates or mammals, they do not characterize Tarsiiformes. For instance, tarsiers don't have the flat noses typical of some other primates; they are primarily nocturnal rather than diurnal; and they do not possess prehensile tails, which are features more commonly found in some New World monkeys. Thus, large eyes for nocturnal adaptation are the definitive characteristic of Tarsiiformes.