When you read, your eyes fixate for a fraction of a second, and then jump to a new point in the text. Your reading experience is continuous because during the jump, the information from the last eye fixation is held in memory.

Sensory memory.

Explanation:

Sensory memory is the type of memory that stores information for a very brief period of time it is even shorter than the time period of  the short term memory.

Sensory memory helps the  brain to hold the effects  of a sensory stimulus for sometime  even after the stimulus has ceased. This helps in continuous perception and processing of data in the brain.

The  expression of continuous reading, writing and speaking are due to the existence of sensory memory.

If sensory memory does not function properly then, the synchronization of words and their understanding would have been impossible.

igneous rocks which formed by the crystallization of magma at the surface of the earth called extrusive rocks. they are characterized by fine-grained textures because the rapid cooling at or near the surface did not provide enough time for large crystals to grow.