Question

Ectoderm forms
(a) Sweat glands
(b) Nervous system
(c) Lens of eye
(d) All of the above

Answer 1

Hint: Three germinal layers are formed in the early stage of embryonic development and they are the ectoderm (outer layer), the mesoderm (middle layer), and the endoderm (inner layer).

Complete answer:
These three layers are formed during the process of gastrulation i.e. when the cells that constitute the blastula begin to differentiate into special cells that become layered of the growing embryo. It represents some of the first multipotent stem cells in embryonic development and gives rise to different parts. The ectoderm also is the initiating part of embryogenesis. This is further classified to surface ectoderm and neural ectoderm. The surface ectoderm differentiates into the epidermis, nails, and hair. The neural ectoderm forms the neural tube and neural crest. These then give rise to the brain, spinal cord, and peripheral nerves. The ectoderm also gives rise to sensory epithelia of the eye, mammary gland, pituitary gland, and sweat gland.
So, the correct answer is 'All of the above'.

Note: The cells from the endoderm form many of the internal linings of the body, for instance, the gastrointestinal tract and respiratory systems. It also gives rise to the lungs, liver, pancreas, and other organs including the upper urogenital tract and female vagina. It also gives rise to certain organs like the colon, the stomach, and the intestines. The mesoderm cells lie between the endoderm and the ectoderm, these cells give rise to all other tissues of the body. They are differentiated into 3 parts Paraxial mesoderm (contains mostly somites which give rise to the axial skeleton, dermis, and muscle), Intermediate mesoderm (gives rise to the gonads, kidneys, and urogenital structures), and Lateral plate mesoderm (further classified into parietal mesoderm and visceral mesoderm that form the limb skeleton and muscular wall of the gut tube, respectively. This layer also distinguishes evolutionarily higher life-forms that have bilateral symmetry from lower life-forms that have radial body symmetry.