In this unit analogy, “Kilometre is to Metre as Tonne is to ______”. Choose the unit that stands in the same larger to smaller measurement relationship as metre does to kilometre.

Introduction / Context:
This question uses an analogy involving metric units of measurement. The pair “Kilometre : Metre” relates a larger unit to a smaller unit of the same physical quantity, namely length. To complete the analogy “Tonne : ?”, you must select the smaller unit that relates to tonne in the same way metre relates to kilometre. Such questions reinforce understanding of the metric system and unit hierarchies.

Given Data / Assumptions:

• First pair: Kilometre → Metre. • Second pair: Tonne → ? • Options: litre, kilogram, hours, weight. • In the metric system, 1 kilometre equals 1000 metres and 1 tonne equals 1000 kilograms.

Concept / Approach:
We first identify the exact relationship in the example pair. Both kilometre and metre are units of length, and a kilometre is the larger unit while a metre is the smaller unit. More precisely, one kilometre equals 1000 metres. Therefore, the second pair should also consist of a larger and smaller metric unit of the same type. Tonne is a large unit of mass, so its corresponding smaller unit should be kilogram, because one tonne equals 1000 kilograms.

Step-by-Step Solution:
Step 1: Understand the first pair. Kilometre is a unit of distance. Metre is also a unit of distance, but smaller, and there are 1000 metres in one kilometre. Step 2: Identify the type of unit for tonne. Tonne measures mass or weight in everyday language, and it is a large metric unit. Step 3: Find the smaller metric unit for mass that fits the same relationship. In the metric system, 1 tonne equals 1000 kilograms, just as 1 kilometre equals 1000 metres. Step 4: Evaluate options. Litre measures volume, not mass. Kilogram measures mass and is exactly 1/1000 of a tonne. Hours measure time. Weight is a general concept rather than a specific unit. Thus, the only unit that stands to tonne as metre stands to kilometre is kilogram.

Verification / Alternative check:
We can summarise the structure of the analogy as “larger metric unit : smaller metric unit of the same quantity”. In numerical form, 1 kilometre = 1000 metres and 1 tonne = 1000 kilograms. No other option produces a similar neat ratio for tonne. Litre, hours, and the general word weight do not create a 1000 to 1 relationship in the context of mass in the way metre does for length.

Why Other Options Are Wrong:
• Litre – relates to volume, not mass, so it breaks the same quantity requirement. • Hours – measures time, unrelated to mass. • Weight – is a general concept, not a standard metric unit; it cannot stand parallel to the specific unit metre.

Common Pitfalls:
Sometimes candidates confuse types of quantities, mixing volume, time, and mass. Others choose the word weight because tonne is informally spoken of as weight, forgetting that analogy questions require two clearly defined metric units with a similar numerical relationship. Keeping track of both the quantity type and the conversion factor leads directly to kilogram as the correct answer.

Final Answer:
The unit that correctly completes the analogy is Kilogram.