Race is to fatigue as fast is to which of the following effects in this cause and effect analogy.

Introduction / Context:
This analogy uses cause and effect relationships. A race is a strenuous physical activity that often results in fatigue. We need to find a similar effect produced by a fast, where fast means a period of going without food for religious, medical or other reasons. Identifying the parallel effect completes the analogy correctly.

Given Data / Assumptions:

• First pair: Race : fatigue.
• Racing causes physical tiredness or fatigue.
• Second pair: Fast : ?
• Options: Weakness, Hunger, Appetite, Food.
• We interpret fast as abstaining from eating.

Concept / Approach:
The relationship is “activity or condition is to its immediate result.” Running a race leads directly to fatigue. Similarly, not eating for a period leads directly to hunger. Weakness is also a possible longer term result of fasting, but the most immediate and direct effect is the feeling of hunger. Appetite is a general desire for food and can exist even without a fast, while food is what is absent during the fast. Hence, hunger is the best single word to describe the effect of fasting parallel to fatigue as the effect of racing.

Step-by-Step Solution:
Step 1: Describe the first pair as a sentence: Taking part in a race causes fatigue. Step 2: Rephrase the second pair in the same way: Going on a fast causes blank. Step 3: Recognise that when people do not eat, they most strongly feel hungry. Step 4: Compare this with other potential results, such as weakness, and decide which is more immediate and universal. Step 5: Select hunger as the direct parallel to fatigue as the result of the respective activity.

Verification / Alternative check:
Consider the time sequence. During a race, even before it ends, people experience fatigue from exertion. During a fast, even before it has lasted very long, people experience hunger due to lack of food. Weakness usually develops over a longer period of extended fasting and may not be the first or most noticeable effect. Appetite is a general liking for food and not specifically caused by fasting. Food itself is the thing missing, not the effect. Therefore, the most precise and immediate effect that matches fatigue is hunger.

Why Other Options Are Wrong:

• Weakness: Can result from long fasting, but it is not as immediate a response as hunger and does not mirror the directness of race causing fatigue.
• Appetite: Refers to desire for food, which may be present even when a person is not fasting.
• Food: This is what is consumed when not fasting and what is absent during the fast but is not an effect.

Common Pitfalls:
Some candidates may be tempted by weakness because it sounds negative like fatigue. However, it is important to match not just the emotional tone but the kind of relationship. Race leads directly to fatigue; fast leads directly to hunger. Checking which effects occur first and most universally during the condition helps avoid confusion in such cause and effect analogies.

Final Answer:
The correct completion is Fast : Hunger, so the analogy reads Race : fatigue :: Fast : hunger.