2. The duckling is flapping its wings and swimming in the river.

The duckling and his mother waddled in the water.

The duckling waddled into the lake and swam happily in it.

The duckling will bury its head in the river for a while, and then it will stretch out and swim happily in the river.

Extended data:

?

There is a special layer of grease on duck feathers, which can ensure that their feathers are not completely soaked by water, so they are easy to float on the water. At this time, as long as the duck paddles backwards, it can move forward by reaction.

Ducks belong to aquatic birds. Ducks have a pair of feet that can paddle, and there is a big fat gland in the tail of ducks, which is called the tail fat gland. Its chest can also secrete a kind of "powder" keratin tablets containing fat.

Usually, I often peck and grind with my mouth, rubbing the fat secreted by the fat glands at the tail and the "powder"-like keratin pieces secreted by the chest hair on the feathers. Therefore, when it enters the water, its feathers will not touch the water, so the duck feathers will not get wet in the water, and there are rich fluff to form an air cavity, which can float on the water without sinking. Ducks have these natural physiological conditions, so they can swim