Not necessary, because even if it was the tomb of a child, the Egyptians might have thought that the child would benefit in the afterlife from breaking the legs of a hippo figurine.

Not necessary, because even if earthenware figures were sometimes used as children’s toys, the argument concerning this particular figure is based on the specific circumstances of the figure. It was in a tomb, upside down, with its legs broken off. These features can signify that an earthenware figure was a religious object, even if other earthenware figures were toys.

Not necessary, because the tomb could have been reentered, perhaps to place the figure to help the deceased person in the afterlife.

Necessary, because if it were not true — if the hippo’s legs WERE broken through a natural occurence after it was placed in the tomb — then the fact the hippo’s legs were broken would not constitute evidence of a religious purpose for the object.

Not necessary, because the reasoning is based on the religious significance of a figure with its legs broken off. But whether the figure was placed upside up or upside down originally has no connection to the religious reasons offered for the conclusion.