Study of improvement of human race through laws of heredity is called EUGENICS.

EUPHENICS : Study of improvement of human race by altering the proteins during mRNA synthesis i.e. protein synthesis process in cells. This is also called medical engineering.

EUTHENICS : Science of improvement of modern generation of man through better nutrition.

Eugenics is the correct answer to the given question.

Eugenics is a concept that involves the application of hereditary principles in order to improve the human race. It focuses on selective breeding to promote desirable traits and eliminate undesirable traits in the human population. The term "eugenics" was coined by Francis Galton, a cousin of Charles Darwin, in the late 19th century.

Eugenics gained popularity in the early 20th century and was primarily influenced by ideas of genetics and social Darwinism. It aimed to improve the genetic quality of the human population by encouraging individuals with desirable traits to reproduce while discouraging or even preventing those with undesirable traits from reproducing. This was often achieved through policies such as forced sterilization, marriage restrictions, and even euthanasia.

Explanation of Options:

a) Euthenics: Euthenics refers to improving the environment to enhance the health and well-being of individuals. It focuses on factors such as nutrition, sanitation, and living conditions rather than genetic factors.

b) Eugenics: As explained above, eugenics is the employment of hereditary principles to improve the human race.

c) Euphenics: Euphenics refers to the improvement of individuals with genetic disorders or disabilities through medical intervention or therapy. It aims to enhance the quality of life for individuals with genetic conditions rather than focusing on improving the overall human race.

d) Ethnology: Ethnology is the study of different ethnic groups, their origins, cultures, and characteristics. It is not directly related to the improvement of the human race through hereditary principles.

In conclusion, eugenics involves the use of hereditary principles to improve the genetic quality of the human population. It gained popularity in the early 20th century but has been widely criticized and discredited due to its association with discriminatory practices and violations of human rights.