Practice question

Development describes sequential transformation from single fertilized egg into complex multicellular adult through orchestrated cellular processes. It integrates fertilization restoring diploidy, cleavage generating blastomeres, gastrulation establishing three germ layers ectoderm, mesoderm, endoderm, organogenesis forming liver, brain, heart, and growth increasing mass. Molecular regulation involves morphogen gradients, Hox positional codes, and differential gene expression. Unlike fertilization which is singular event, or differentiation limited to cell specialization, development encompasses entire lifespan from embryogenesis to aging, linking genetic information to phenotypic outcome via precisely timed proliferation, migration, and morphogenesis.