Which structure of the brain is primarily involved in coordination and balance?

A. It is present at birth and provides immediate defense: This describes innate immunity, which is nonspecific and provides immediate protection against pathogens without prior exposure.

B. It involves skin and mucous membranes as barriers: Physical barriers such as skin and mucous membranes are part of innate immunity and do not confer the specificity associated with adaptive immune responses.

C. It does not involve antibodies: Specific immunity relies heavily on antibodies produced by B lymphocytes to recognize and neutralize specific pathogens. The absence of antibodies would indicate nonspecific defense.

D. It can remember previous encounters with pathogens: Specific (adaptive) immunity has memory, allowing the immune system to respond more rapidly and effectively upon subsequent exposure to the same pathogen. Memory cells, including B and T lymphocytes, are responsible for this enhanced response.

A. Photoreceptors: Photoreceptors are specialized cells in the retina that detect light and color, playing a role in vision. They do not respond to temperature changes.

B. Chemoreceptors: Chemoreceptors detect chemical changes in the environment or body, such as oxygen, carbon dioxide, and pH levels. They are not involved in sensing temperature.

C. Thermoreceptors: Thermoreceptors are sensory receptors located in the skin and hypothalamus that respond to changes in temperature. They allow the body to perceive warmth and cold and help regulate thermoregulation.

D. Mechanoreceptors: Mechanoreceptors respond to mechanical stimuli such as pressure, touch, vibration, and stretch. They do not detect temperature changes.