Most penguins live in a land of snow and ice. They have feathers, wings, and a beak like other birds. But they are different in two important ways. Penguins cannot fly. A penguin body is too heavy. Its wings are small, flat, and stiff. The feet of a penguin are made for swimming, not walking. Penguins look funny as they waddle across land. If they want to move quickly on land, they flop down on their bellies and slide. In the water they use their webbed feet to help them swim. The way penguins use their wings in different, too. They use their flat, stiff wings as flippers to help them swim swiftly through the cold water. They swim as well as the fish, seals, and whales. When a penguin is hungry, it dives into the ocean and hunts for food. Penguins eat shrimp like animals called krill. They also eat squid and fish. Penguins lay eggs like all birds. Some kinds of penguins make a nest of pebble. One kind holds the egg on its feet. The penguin covers the egg with a flap of skin to keep it warm. Penguin chicks are covered with fluffy feathers when they hatch. Both the mother and father penguin feed the baby. When the chick grows adult feathers, it will go to the ocean to get its own food.
Which of these sentences from the passage does NOT tell how penguins move.