A newborn is an infant who is less than one month old. This stage of life is crucial for development, as babies undergo rapid physical and neurological changes. Newborns typically weigh between 5.5 to 10 pounds and measure about 18 to 22 inches in length. They rely entirely on their caregivers for nourishment, usually through breast milk or formula. During the first few weeks, newborns spend most of their time sleeping, waking only for feeding and diaper changes. Their vision is limited, and they can only see objects that are about 8 to 12 inches away. Newborns also exhibit reflexes, such as the rooting reflex, which helps them find food.