In the provided observations, we see that like charges repel each other, while opposite charges attract.
In this scenario, both objects have a charge of +1 C and are 10 mm apart. Referring to the table, we find that when two charges of the same sign (+1 C and +1 C) are involved, they produce a repulsive force. The nearest observed distance of 4 mm with +1 C and +1 C is noted as producing a "medium" force.
Since the distance of 10 mm is greater than 4 mm, but still within a range where we can infer the relationship, we can conclude that the repulsive force will be present but will likely be weaker than the "medium" observation at 4 mm.
Therefore, the most appropriate response regarding the type and strength of the electric force between the two charges at a distance of 10 mm would be:
Repulsive, weak.