Which function allows sprites to fade in or out in CodeHS?

The function that enables sprites to fade in or out in CodeHS is setOpacity(value) when combined with a gradual change in a loop. This method is effective because it allows for the manipulation of a sprite's opacity over time, creating a smooth transition effect. By adjusting the opacity incrementally within a loop, you can achieve the desired appearance of fading in from fully transparent to fully opaque or fading out from opaque to transparent.

The essence of fading involves modifying the opacity value, which ranges from 0 (completely transparent) to 1 (completely opaque). By using a loop to gradually increase or decrease this value, you create a dynamic visual effect that is smooth and visually appealing.

The other options may suggest methods related to visibility but do not specifically provide the direct control over opacity changes necessary for a fade effect. Therefore, utilizing setOpacity(value) with a loop effectively implements the fading feature for sprites.