Final answer:
The line "He lay in his bed with his beating heart." in the passage "The Veldt" by Ray Bradbury is an example of foreshadowing.
Step-by-step explanation:
The line "He lay in his bed with his beating heart." in the passage "The Veldt" by Ray Bradbury is an example of foreshadowing. Foreshadowing is a literary device used to hint at future events or outcomes. In this case, the beating heart is a foreshadowing of a potential danger or suspenseful situation that will occur later in the story.