Question

which condition must exist in order for conduction to occur between two substances?
the molecules of the substances must be touching.
both substances must be the same temperature.
at least one substance must be a liquid.
most of the molecules must be slow moving.

Explanation:

Conduction is heat transfer through direct contact. Molecules need to be in contact for heat - energy to be transferred from one substance to another by conduction.

Answer:

The molecules of the substances must be touching.