Final answer:
The dog's weight remained the same despite eating sweets.
Step-by-step explanation:
Weight gain in a living organism can be attributed to various factors including the intake of food and energy. In this case, the dog initially weighed 40 kg and then ate 5 kg of sweets. However, the dog's weight remained the same at 40 kg. This could be due to the fact that the energy stored in the sweets was equivalent to the energy expended by the dog, resulting in no net weight gain. It's important to consider that food intake alone does not always directly translate to weight gain, as energy expenditure and metabolism play a crucial role in the equation.