Final answer:
Birds use their wings primarily for flight, which is achieved by flapping them, using chest muscles like the pectoralis major and the supracoracoideus. However, not all birds fly; some species have adapted their wings for other purposes, such as swimming in the case of penguins. Birds do not use their wings to grasp; that function is served by their feet.
Step-by-step explanation:
Birds use their wings primarily for flight or, in some cases, adapted forms of movement. The wings are modified front limbs which birds move using muscles in the chest, particularly the pectoralis major for the downward stroke and the supracoracoideus for the upward stroke. These muscles are large and may make up to 35 percent of a bird's body weight, indicating the importance of flight in most avian species. However, not all birds can fly. For example, the wings of a penguin are adapted into flippers for swimming, whereas a kiwi, a flightless bird, does not have fully developed wings for flight.
While the evolution of wings in birds has been a subject of scientific speculation, two main hypotheses suggest that wings evolved either as a means to leap higher from the ground or to glide from branch to branch in tree-dwelling ancestors. Regardless of the evolutionary origins, the primary function of bird wings in today's avian species is generally flight, although different birds have specialized their wings for various purposes, such as the penguin's adaptation for swimming.
Thus, in response to the student's question, birds use their wings to flutter, not to grasp. Grasping is the function of a bird's feet, which can vary greatly among different birds, such as webbed feet for swimming and long toes for walking on soft surfaces.