Which of the following is the first step of growth and development?

Growth and development are commonly studied across several domains — physical (bodily and motor), mental/cognitive, social, emotional, and moral. These domains develop at overlapping but not identical rates through childhood; among them, one domain is understood to begin earliest and is the most immediately observable from birth.

The body's growth in size, organs, and motor ability begins at conception itself, well before a child shows language, reasoning, social role-taking or moral judgement. Because bodily/motor change is observable from the earliest days of life — earlier than the behaviours associated with the other domains — physical development is treated as the first step of the developmental sequence in this framing.

• Social development (learning to interact with family, peers, and community) requires abilities — communication, some independence — that only emerge over the following months and years, so it takes hold well after the earliest changes are already under way.

• Moral development (judging right from wrong, understanding rules) depends on abstract reasoning that itself matures only later in childhood, making it, of these four domains, one of the last to be established rather than the first.

• Mental (cognitive) development — perception, memory, language, reasoning — becomes evident only gradually through infancy and early childhood as the child gains experience, so it does not mark the opening stage of the sequence on its own.