Methanoic acid is normally found in :

Methanoic acid, commonly known as formic acid, is the simplest carboxylic acid and is naturally found in the stings of ants and nettle leaves [2]. When an ant bites, it injects this acidic liquid into the skin, causing pain, redness, and irritation [1]. This effect can be neutralized by applying a mild base like baking soda [3]. While formic acid can appear in the human body as a toxic metabolite of methanol—potentially leading to brain damage or metabolic acidosis—it is not a normal constituent of the healthy human brain, muscles, or urine in significant quantities [1]. In nature, it serves as a defense mechanism for various insects, including ants and bees, to deter predators [3]. Therefore, among the given options, ant stings are the primary natural source where methanoic acid is normally found.

Sources

1. [2] Science , class X (NCERT 2025 ed.) > Chapter 2: Acids, Bases and Salts > Table 2.3 Some naturally occurring acids > p. 28
2. [1] Science-Class VII . NCERT(Revised ed 2025) > Chapter 2: Exploring Substances: Acidic, Basic, and Neutral > 2.3 Neutralisation in Daily Life > p. 18
3. [3] Science , class X (NCERT 2025 ed.) > Chapter 2: Acids, Bases and Salts > Self defence by animals and plants through chemical warfare > p. 27