[Solved] Which of the following chromosomal abnormalities most severely affect a fetus? A)XXX B)Monosomy for a large autosome C)Trisomy 21 D)XXY Brain Damage: null Stimuli: External or internal factors that elicit a response or reaction from organisms. Automatic Response: An involuntary reaction to a stimulus that occurs without conscious thought as a result of learning or biological predisposition. Rooting: A reflex in infants that prompts them to turn their head towards anything that touches their cheek, aiding in the act of breastfeeding.