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.

there are 35 white marbles

step-by-step explanation:

y- yellow marbles

4y + 5 = 45

subtract 5 from both sides

4y = 40

divide for from both sides

y = 10

plug in 10 to get 40 yellow marbles then subtract by 5 to get 35 marbles

thus there are only 10 yellow marbles