Question

The accidental touch of nettle leaves creates a burning sensation , which is due to inject of

Answer 1

The Accidental touch of nettle leaves creates a burning sensation because it injects formic acid, acetylcholine and histamine when its cell sap are under pressure.
Even the slightest touch breaks off their little tips, the broken tip then forms a sharp edge, which pierces the stinging hair into the skin and then sensation happens

Answer 2

Urtica dioica, commonly known as the stinging nettle is a herbaceous perennial flowering plant in the family Urticaceae. It is native to Europe, Asia, northern Africa, and North America.
The species is divided into six subspecies, five of which have many hollow stinging hair or tips called trichomes on the leaves and stems. These tips come off when touched, transforming the hair into a needle that can inject several chemicals like Formic acid, Histamine, Acetylcholine, and Serotonin causing a painful sting or paresthesia, giving the species its common names, the stinging nettle.