During gastrulation, the embryo develops three germ layers (endoderm, mesoderm, and ectoderm) The structures derived from ectoderm are
(i) pituitary gland (ii) cornea (iii) kidneys (iv) notochord

Options

A. (i) and (iii)
B. (ii) and (iii)
C. (i) and (ii)
D. (ii) and (iv)

Explanation

To determine which structures are derived from the ectoderm during gastrulation, we can analyze each option provided:

1. **Understanding Germ Layers**: During gastrulation, three primary germ layers are formed: ectoderm, mesoderm, and endoderm. Each layer gives rise to specific tissues and organs in the developing embryo.

2. **Identifying Ectoderm Derivatives**:
- **Ectoderm**: This is the outermost layer and is responsible for forming structures such as the skin, nervous system, and certain glands.
- **Endoderm**: This layer forms the lining of the digestive tract and organs such as the liver and pancreas.
- **Mesoderm**: This middle layer gives rise to muscles, bones, the circulatory system, and kidneys.

3. **Analyzing Each Option**:
- **(i) Pituitary Gland**: The pituitary gland is derived from the ectoderm. It originates from a structure called Rathke's pouch, which is an ectodermal outgrowth.
- **(ii) Cornea**: The cornea, which is part of the eye, is also derived from the ectoderm. It develops from the surface ectoderm.
- **(iii) Kidneys**: The kidneys are derived from the mesoderm. They develop from the intermediate mesoderm.
- **(iv) Notochord**: The notochord is also derived from the mesoderm. It plays a crucial role in the development of the vertebral column.

4. **Conclusion**: From the analysis, the structures derived from the ectoderm are:
- **Pituitary Gland (i)**
- **Cornea (ii)**

Thus, the correct answer is that the structures derived from ectoderm are (i) Pituitary gland and (ii) Cornea.