Transgenic animals can be specifically designed to allow the study of…

The correct answer is Option (1) → B, C and D only

A transgenic animal carries a foreign gene that has been added to its genome. Such animals are made for several purposes.

A. Antigen-antibody interactions — Incorrect. This is not one of the purposes for which transgenic animals are designed. It is the principle behind tests such as ELISA.

B. Regulation of genes — Correct. Transgenic animals help to study how genes are regulated.

C. Effects on the normal functioning of the body — Correct. They help to study how genes affect the normal functions of the body and its development.

D. Investigation of new treatments for diseases — Correct. Transgenic models of human diseases, such as cancer and Alzheimer’s, are used to study the disease and to test new treatments.

NCERT Extract:
Transgenic Animals – “… (i) Normal physiology and development: Transgenic animals can be specifically designed to allow the study of how genes are regulated, and how they affect the normal functions of the body and its development, e.g., study of complex factors involved in growth such as insulin-like growth factor. By introducing genes from other species that alter the formation of this factor and studying the biological effects that result, information is obtained about the biological role of the factor in the body.”
Transgenic Animals – “… (ii) Study of disease: Many transgenic animals are designed to increase our understanding of how genes contribute to the development of disease. These are specially made to serve as models for human diseases so that investigation of new treatments for diseases is made possible.”