Which region of the Ig molecule interacts with the antigen? What makes the region suited for this purpose?

Answer and Explanation:

Immunoglobulins (Ig) are proteins that are composed of 4 polypeptidic chains: 2 heavy chains (H) and two light chains (L). They assemble in a structure with a 'Y' form. This structure has two regions: the Fab region and the Fc region.

The region of Ig which interacts with the antigen is the Fab region. That is possible because the Fab region presents variability in the amino acid sequence which determines the specific complementary shape with the antigen structure (like a lock and the key).

answer: angiosperms

dicots

angiosperms are highly evolved plants, they produce seeds which are enclosed within in a carple. these are the largest group of plants on earth. they include trees, shrubs, herbs and small flowering plants. angiosperms exhibit a flowering stage in their life cycle. the flower serves the function of reproduction and fruit formation in majority of angiosperms. dicot is the term used to describe flowering plants that have two seed leaves. dicots are plants which develop seeds which split into two parts called cotyledons. each cotyledon contains one embryo.

here, a small purple flower development indicates that the plant belongs to angiosperms and having two embryonic leaves indicates it belongs to dicots.