The correct answer to fill in the blank is echoic.
Explanation:
Echoic memory is a type of sensory memory that consists of storing an auditory stimulus (in the primary auditory cortex of the brain) for a few seconds in order to process it and understand it. This is what differentiates it from iconic memory (a type of visual memory), that doesn't last as long as the echoic one, for the visual stimulus can be repeated by observing the image again (which can't happen when hearing something, unless the same sound is repeated by the one that produces it).
The most obvious difference: A sperm cell is a reproductive cell of males while egg cells are of females. Both egg cells and sperm cells depend on each other for the reproduction of a human life. Both egg cells and sperm cells undergo meiosis.
