Answer:
Even when conditions are dismal or less than ideal, pride is often a powerful force that guides the actions of living creatures.
Step-by-step explanation:
The sentence selected above can give Caleb a more efficient way so that he can complete his activity. That's because this sentence sums up well what happened to the dogs pulling the sled even in disadvantageous environmental conditions and even bad physical conditions. They were motivated by their pride in completing that duty, even if it hurt them. Even though they reached the destination they wanted badly hurt, pride gave them the strength to continue.