Quick and Quack were two brave little ducks who lived with their mother. Both were really fast and were always competing against each other.  One day, after visiting their uncle Ducklass, Quack shouted, "Last one home is a goose!" and both ducks swam quickly down the river. They both knew the way well, but               Quack had been preparing a trick for some time. He had realized that the current   in the middle of the river was stronger, and would help him. So, even though Mother Duck had told them never to swim in the middle of the river, Quack paddled   over to it. "I'm old enough now to swim here," he thought to himself. It wasn't long before he realized his mother had been right. He was going much faster than Quick, and was developing a big lead. Quick was not amused. He never disobeyed his mother, and now he was going to lose the race! As they went on, the current got stronger.  Quack proudly crossed the finishing line, without realizing he headed straight for a big whirlpool   in the middle of the river. Before he could react, he was turning around in it, unable to escape. No duck was strong enough to swim in those waters, and poor Quack kept swallowing water. The fact that he was struggling hard didn't help matters much either. Fortunately, a cow from a nearby farm came by, and seeing Quack, he jumped in and rescued him. When he was on dry ground, he remained uncomfortable for quite some time. That provided quite a laugh for different animals that had been watching. By saying "Last one home is a goose", Quack was   _  .
encouraging a competition between himself and Quick setting an example to Quick expressing his desire to get home as soon as possible warning Quick of the danger from their natural enemy