Given a text, write a compressed version of it in a single sentence.
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Question: Daniel Hungerford observed that the Richmond-Kotelchuck model suggests that changes in practice result from effort applied to all three elements of the model-political will, social strategy, and knowledge base. It might seem that research activities apply only to the knowledge base aspect of the model.

Answer: Hungerford observed that the Richmond-Kotelchuck model suggests that changes in practice result from effort applied to will, social strategy, and knowledge base. It seems that research apply only to the knowledge base aspect.

Question: Justice James R. Zazzali and Justice Virginia Long said in a separate opinion that in addition to the reasons given in the majority opinion, also written by Zazzali, they believed the death penalty would constitute cruel and unusual punishment because of Nelson's history of emotional disturbance.

Answer: Justice James R. Zazzali and Justice Virginia Long said that in addition to the reasons given in the majority opinion, they believed the death penalty would constitute cruel and unusual punishment.

Question: As mail volume increases in postal systems, variable costs (processing and transportation) increase and fixed costs decrease as a percentage of total costs. Therefore, street delivery costs, which are largely fixed, decrease as a percentage of total costs as volume increases.

Answer:
As mail volume increases in postal systems, variable costs increase and fixed costs decrease as part of total costs. Thus, street delivery costs decrease as percentage of total costs as volume increases.