Which condition is characterized by relaxed muscles and lack of tone?

Flaccidity is the condition characterized by relaxed muscles and a lack of tone. In this state, the muscles are weak and exhibit diminished resistance to passive movement, which often leads to difficulties with motor control and mobility. Flaccidity can occur as a result of various neurological conditions or injuries that affect the signals transmitted from the nervous system to the muscles.

In contrast to flaccidity, hypertrophy refers to an increase in muscle size due to an increase in the cross-sectional area of the muscle fibers, often resulting from consistent exercise or resistance training. Spasticity involves continuous contraction of certain muscles, leading to stiffness or tightness that can restrict movement. Rigidity also refers to stiffness, but it is characterized by a resistance to passive movement and hypertonicity in muscles, often seen in conditions like Parkinson's disease. These distinctions help highlight why flaccidity, with its specific features of muscle relaxation and low tone, is the correct answer.