Final answer:
Flies have two pairs of wings that serve not only for flight but also for other functions such as protection and communication. These wings are part of the insect's thorax and show great variation in form and function across different insect species.
So, the correct answer is b) two pair.
Step-by-step explanation:
Flies, like many other insects, have two pairs of wings attached to their thorax. These wings are essential for flight and come in different forms and functions among various insect species. For instance, beetles have protective hard wing covers, while katydids use their wings to produce sounds for mating.
In the cases of butterflies, their wings have functions beyond flight, such as camouflage, thermoregulation, and mate selection. Despite the different utilizations, the general structure for flight is common across these insects. This illustrates how wings, while different in form, enable the essential function of flight among flying insects.
So, the correct answer is b) two pair.