EVERYDAY SCIENCE

Detailed explanation-1: -The gastrointestinal (GI) system involves three germinal layers: mesoderm, endoderm, ectoderm. Mesoderm gives rise to the connective tissue, including the wall of the gut tube and the smooth muscle. Endoderm is the source of the epithelial lining of the gastrointestinal tract, liver, gallbladder, pancreas.

Detailed explanation-2: -During neurulation, ectoderm differentiates into two parts. The first is the surface ectoderm, which gives rise to tissues on the outer surface of the body like epidermis, hair, and nails. The second is the neuroectoderm, which forms the nervous system of the embryo.

Detailed explanation-3: -The epidermis begins developing from the surface ectoderm at the end of the fourth week of life as the neural tube separates from the overlying ectoderm to mark the completion of neurulation. Although after the first few weeks of embryogenesis, the epidermis is composed of five strata or layers.

Detailed explanation-4: -Explanation: The process of gastrulation generates the three primary germ layers (ectoderm, endoderm, mesoderm). This is one of the most important steps of development.