Final answer:
A person from birth to 1 month old is termed a 'neonate.' The neonatal period is a time of rapid growth and development, including acquiring key reflexes necessary for survival. Infancy covers the entire first year of life post-birth and involves crucial motor, sensory, and cognitive milestones.
Step-by-step explanation:
From birth to 1 month old, a person is called a newborn. The term specifically used for this early stage is neonate. During the neonatal period, which spans the first to the thirtieth day of life outside of the uterus, the neonate goes through many adjustments and rapid development. The umbilical cord is cut shortly after birth, leaving behind a stump that will eventually dry out and fall off to form the navel. Infancy is defined as the first year of life following birth, a time during which the child experiences significant growth including doubling in length and tripling in weight.
Other important developments during infancy include motor, sensory, and cognitive abilities, also known as developmental milestones. For example, the visual acuity of a newborn is not fully developed, and they show limited color and depth perception. However, their senses of touch and hearing are well-developed from birth. Reflexes such as crying for communication, suckling, and the rooting reflex to find a nipple, are vital for the baby's early survival. Additionally, the first teeth, often called deciduous teeth, usually emerge around six months of age.