Shaking a baby can lead to which of the following severe consequences?

Shaking a baby can lead to permanent brain damage because the infant's brain is still developing and is highly vulnerable to trauma. When a baby is shaken, the violent motion can cause the brain to move back and forth within the skull, leading to bruising, swelling, and bleeding in the brain. This type of injury, commonly referred to as Shaken Baby Syndrome, can result in severe and lasting consequences, such as cognitive deficits, physical disabilities, and even death.

The other options presented do not accurately reflect the effects of shaking a baby, as excessive happiness, positive growth, and improved speech development are not outcomes associated with such trauma. Instead, the consequences of shaking a baby are serious and can fundamentally alter their health and development.