In zoology and chemistry, formic acid occurs naturally as a defensive secretion and is abundantly produced by which of the following organisms?

Introduction / Context:
Formic acid is the simplest carboxylic acid and its common name is derived from the Latin word for ant. It is naturally produced by certain insects and is involved in defence and communication. This question checks whether you can recall which insect is most famously associated with formic acid production in nature.

Given Data / Assumptions:

• Formic acid has a strong, pungent odour and can cause irritation.
• The name formic is related historically to ants.
• Several insect groups are listed as options, but only one is closely linked with formic acid.
• We assume basic school level knowledge of natural sources of simple acids.

Concept / Approach:
The name formic acid comes from formica, the Latin word for ant. Many species of ants, especially red ants, secrete formic acid as a defence mechanism against predators or when disturbed. They can spray or inject this acid through their stings or glands, causing a burning sensation. White ants, which are termites, do not typically use formic acid as their main defensive chemical. Cockroaches and mosquitoes also have different chemical secretions and are not famous for producing formic acid. Therefore, the correct answer is red ants.

Step-by-Step Solution:
Step 1: Recognise that the word formic is historically linked with ants. Step 2: Recall that red ants are known to possess formic acid in their defensive secretions. Step 3: Compare with white ants, which are termites with a different biology and chemistry. Step 4: Note that cockroaches and mosquitoes are not commonly described as major natural sources of formic acid. Step 5: Conclude that red ants are the organisms most strongly associated with natural formic acid production.

Verification / Alternative check:
Chemistry and biology references often mention that formic acid was first isolated by distilling bodies of ants. Descriptions of ant venom and defensive sprays also list formic acid as a major component, especially in many red ant species. The etymology of the term reinforces this connection, since scientists chose the name to reflect the ant origin. These facts strongly support red ants as the correct answer.

Why Other Options Are Wrong:
Option a, white ants, refers to termites, which primarily use other chemicals and structural defences rather than formic acid as their main weapon.

Option b, cockroaches, can produce odorous secretions but are not recognised as significant producers of formic acid.

Option d, mosquitoes, are important disease vectors due to their bites but do not inject formic acid as a defensive chemical.

Common Pitfalls:
Some learners may mix up ants and termites because both can live in social colonies and infest houses, leading them to pick white ants by mistake. Others might guess mosquitoes because they cause irritation after biting, but that irritation comes from saliva proteins, not formic acid. Focusing on the historical origin of the name formic acid is a good way to remember that red ants are the classic natural source.

Final Answer:
Formic acid is produced in significant amounts by Red ants.