Dorsal-ventral patterning within the ectoderm of the Drosophila embryo requires seven zygotic genes including sog (short gastrulation). Sog is expressed in the ventrolateral region of the embryo that gives rise to the nerve cord.
Biology explores the interconnectedness of all living things and the environment. Through learning in biology, students discover that life involves interactions at all levels of organisation: cells interact with their environment and with each other, so do organs, organisms and ecosystems.
molecular biology is the study of the molecular processes of life, especially as applied to genetics. it doesn't study the chemical properties of life overall, as that's for chemists and biochemists; it instead narrowly focuses on genetic mechanisms.