When we stop using learned information, the that support our knowledge weaken and ultimately degrade--and we forget what we once knew?

Synapses

Explanation:

A synapse is a structure that allows a neuron to pass a signal to another neuron. Therefore, synapses are the elements that enable neurons to connect to each other. Synapses are essential to communicating information in the nervous system. However, when we stop using learned information, the synapses that supported our knowledge weaken, eventually degrading. When this occurs, we forget what we once knew. An example of this is someone forgetting a foreign language after not practicing it for a long time.