What happens in a reduction half-reaction?
elements gain electrons
elements lose electrons
oxygen is added
oxygen is lost

Option (a) is the correct answer.

Explanation:

A reduction-half reaction is defined as the reaction in which there occurs gain of one or more number of electrons by a specie or element.

Or, in a reduction-half reaction there occurs loss of oxygen if it is present in a reaction.

But in a reduction-half reaction loss of electrons will always take place.

For example,

Reduction-half reaction:

So here, oxidation state of copper is changing from +2 to 0. Also, loss of oxygen is occurring in the reaction equation.

Oxidation-half reaction:

Thus, we can conclude that in a reduction half-reaction elements gain electrons.

conduction is the transfer of thermal energy (heat in transfer) due to collisions between the molecules in the object. collisions between adjacent atoms and molecules transfer kinetic energy from the warmer to the cooler object. the objects must be in physical contact.