How Is the Relay (Secondary)section of an FMVSS-121 Compliant Dual-Circuit

question 16

Multiple Choice

How is the relay (secondary) section of an FMVSS-121 compliant dual-circuit foot valve actuated when the air brake circuit is functioning properly?

• A) pneumatically
• B) mechanically
• C) both mechanically and pneumatically
• D) by foot pressure alone

---

Definitions:

Antihistamines

Medications used to relieve or prevent the symptoms of allergic reactions by blocking the action of histamine, a substance in the body that causes allergic symptoms.

Allergies

A hypersensitive immune response to typically harmless substances in the environment, such as pollen, food, or dust, leading to symptoms like itching, swelling, and difficulties breathing.

Prefrontal Cortex

A region of the frontal lobes of the brain associated with decision making, social behavior, and personality.

Substantia Nigra

A region of the brain involved in movement control and reward; it plays a significant role in diseases such as Parkinson's.