(Of leaves or flowers) reacting to touch with movement (e.g. as the rachis and leaflets of Mimosa pudica).

Reacting to touch by moving, as in Biophytum sensitivum (Oxalidaceae), Dionaea muscipula (Droseraceae) and Mimosa pudica (Fabaceae).

Able to detect and respond to an outside stimulus.

Haying an unexpected reaction to an allergen or to a drug, caused by the presence of antibodies which were created when the person was exposed to the drug or allergen in the past.

Possessing the ability to respond to a stimulus. The cells of the retina, for example, are sensitive to the stimulus of light and respond by sending nerve impulses to the brain. Other receptors are sensitive to different specific stimuli, such as pressure or the presence of chemical substances.

When a particular pathogen, which we shall refer to as BMS, invades an organism, the organism may react with severe symptoms. Additionally, sensitivity can be observed when the affected organism is unable to endure the action of a harmful or pathogenic element, such as a pathogenic organism or virus, without a strong reaction. This reaction can result in various degrees of symptom expression and damage, which we will refer to as APS.

Having the ability to react to stimuli; occasionally used to describe situations involving extreme or abnormal reactions to stimuli.