What made the dog, the horse and the ox very angry?
All the three animals, the dog, the horse and the ox were angry because they had been asked to do extra work while the camel did absolutely no work.
The camel was looking at his own reflection in the pool. What does it suggest to you about the camel?
The camel's looking at his own reflection in the pool shows that he was vain of his gain looks, especially his back. He was looking into water to admire himself.
What tasks, do you think, were assigned to the dog and the ox?
The dog was assigned the task of fetching and carrying the things. The duty assigned to the ox was to carry the yoke on his neck and plough the field.
How did the Djinn know the horse was complaining against the camel?
The Djinn that the horse was complaining against the camel because he was the in charge of all deserts and knew about everything happening in relation to his deserts.