In the classification analogy “Reptile is to lizard as flower is to ____”, which option best completes the category–member relationship?

Introduction / Context:
This analogy is based on category and example. A reptile is a broad class of animals, and a lizard is a specific member of that class. In the same way, a flower is a broad category in the plant world, and the second term must be a specific example of a flower. The question checks whether you can identify which option names a type of flower rather than a part of a flower or a different plant structure.

Given Data / Assumptions:

• First pair: Reptile and lizard.
• Second pair: Flower and an unknown term.
• Options: orchids, stem, leaf, petal, thorn.
• We treat “reptile” and “flower” as categories, and “lizard” as a member.

Concept / Approach:
The structure of the first pair is “group to member.” Reptile is a class that includes lizards, snakes, and other animals. For the second pair, flower is a group, so the missing term must be a particular kind of flower, not a physical part of a flower. Among the options, orchids are a family of flowering plants and are widely known as ornamental flowers. The other options describe plant parts rather than varieties of flowers.

Step-by-Step Solution:

Step 1: Analyse the first pair: reptile is a category, and lizard is an animal that belongs to this category. Step 2: Determine the relationship type as “class to example of that class.” Step 3: For the second pair, flower is the class, so the second term must be a specific example of a flower. Step 4: Among the options, orchids are recognised as ornamental flowers that come in many species and colours. Step 5: Stem, leaf, petal, and thorn are structural parts of plants or flowers, not specific kinds of flowers, so they cannot fulfil the same role as lizard does for reptile.

Verification / Alternative check:
You can verify the pattern by replacing words in the first pair with other examples. For instance, “bird : sparrow” or “fruit : apple” follow the same format. In the plant world, a parallel would be “flower : rose” or “flower : orchid.” Orchids fit this pattern exactly. In contrast, stem or leaf would correspond more to “animal : leg,” which is a part whole relation, not class member. Therefore, orchids is the correct choice to preserve the class member structure.

Why Other Options Are Wrong:
Stem supports the plant and may hold flowers but is not itself a flower type. Leaf is a photosynthetic organ and again not a flower variety. Petal is a part of a single flower, just as a scale is part of a reptile, and thorn is a protective structure on some plants. None of these represent a named example of the broader class “flower” in the same way that lizard represents an example of “reptile.”

Common Pitfalls:
A typical mistake is to think of parts of the flower and choose petal because it seems closest in everyday association. However, that changes the relationship from class member to whole part. In such analogies, it is helpful to label one term as a class or whole and check whether the second term is an example or a component, and then mirror that same logic in the second pair.

Final Answer:
The correct completion is that flower is to orchids as reptile is to lizard.