Question

Eyes lens is formed from?

Answer 1

Hint: This is the outermost layer that is formed during embryonic development. The differentiation of the outer layer of germ cells results in the formation of this layer. The cells of this layer form various internal and external structures of the organism.

Complete answer-
To solve the question we should know about the differentiation of inner cell mass and the structures that are formed after differentiation. After implantation, three layers are formed due to the inner cell mass differentiation. These cell layers are ectoderm, endoderm and mesoderm.
The ectoderm is the outermost layer that is involved in the formation of various structures such as skin, mouth, some glands and various sensory organs. The ectoderm is of two types- neural and surface ectoderm. The cells of the surface ectoderm help in the formation of cornea and eye lens.
The mesoderm is present between ectoderm and endoderm. It is the middle layer, the cells of which form blood, bone, adipose tissue, muscle cells etc.
The ectoderm is the innermost layer that is primarily involved in the formation of epithelial tissue. It forms the outer covering of gut and respiratory organs. The cells of the endoderm are columnar in shape.

Thus the answer to the above question is surface ectoderm as the cells of the ectoderm form the surface of the eye lens and other sensory organs.

Note:
In diploblasts, only two layers i.e. ectoderm and endoderm are present while in triploblasts three layers are present. The ectoderm is mainly involved in the formation of the nervous system and skin while the endoderm is mainly involved in the formation of various organs of the digestive system. Connective tissue and muscular systems are formed from mesoderm.