With regard to metabolic reactions, what does it mean when someone says a molecule has been "reduced"

Example is conversion of NAD+ to NADH+ is an example of reduced in metabolism.

Explanation:

Oxidation and reduction or redox reaction means transfer of electron from one atom to another in a compound.

In photosynthesis and respiration redox reaction are seen.

The substance that gain the electrons in  metabolic reaction is said to be reduced.

In respiration process oxygen is being reduced. The NAD+ accepts hydrogen ion  and 2 e- to become NADH+H+. These are electron carriers.

The reactions can be seen in glycolysis, Kreb's cycle.

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after receiving a stimus, the sensory receptors send(s) signals to the appropriate area of the body.  

the must be sensory neurons.  

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