In the biological analogy “Tadpole is to frog as larva is to ____”, which option best completes the relationship between juvenile and adult forms?

Introduction / Context:
This analogy question checks your understanding of basic biological life cycles and classification. The pair “Tadpole : frog” represents a juvenile stage and its corresponding adult form in amphibians. To solve the second half “larva : ?”, you must know which broad group typically has a larval stage that later transforms into an adult of that group. Such questions frequently appear in aptitude and general science based reasoning sections.

Given Data / Assumptions:

• First pair: Tadpole is related to frog.
• Second pair: Larva is related to an unknown adult group.
• Options: insect, spider, worm, amphibian, reptile.
• We assume standard school level biology definitions of life stages.

Concept / Approach:
A tadpole is the aquatic, juvenile stage in the life cycle of a frog. In the same way, a larva is the immature stage in the life cycle of many insects. The pattern in the analogy is therefore “juvenile form is to adult animal as juvenile form is to adult animal.” We only need to identify the group for which “larva” is the recognised immature form leading to an adult of that group.

Step-by-Step Solution:

Step 1: Understand the first pair. A tadpole is the young form of a frog before metamorphosis. Step 2: Recognise the relationship: “young stage of an organism is to adult organism.” Step 3: Apply the same idea to “larva”. A larva is the immature stage of many insects such as butterflies, beetles, and flies. Step 4: Check which option names the group whose adult form arises from a larval stage. That group is insects. Step 5: Confirm that none of the other options represent the standard adult group for an organism called “larva”.

Verification / Alternative check:
Think of common examples. A caterpillar is the larval stage of a butterfly, and maggots are larval stages of certain flies. Both butterfly and fly are insects. The same is true for many beetles and moths. While some other groups can have juvenile forms, the term “larva” in basic biology is most strongly associated with insects. This matches the structure “tadpole (juvenile) is to frog (adult)” and “larva (juvenile) is to insect (adult).”

Why Other Options Are Wrong:
Spider is an arachnid; its young are not usually described simply as “larva” in basic school terminology. Worm is itself a type of organism, not a mature stage of something called larva in this context. Amphibian and reptile are broad vertebrate classes and do not match the direct, textbook association with the word “larva” the way insects do. Therefore they do not fit the precise biological analogy.

Common Pitfalls:
Students sometimes pick “worm” because many larvae look worm like. However, the analogy focuses on life stage versus adult group, not shape. Others may select “amphibian” or “reptile” simply because tadpoles belong to amphibians and they try to mirror that with another large group, which breaks the specific juvenile to adult structure. Always ask what group most commonly has “larva” as a named life stage.

Final Answer:
The correct completion of the analogy is that a larva develops into an insect.