Charles Darwin, the famous evolutionist, proposed his theory of evolution in which of the following books?

Introduction / Context:
This question checks your understanding of basic history of science and evolutionary biology. Charles Darwin is one of the most important figures in biology, and his book that first systematically presented the theory of evolution by natural selection is regularly asked in examinations. Knowing the exact title of this foundational work helps you distinguish between Darwin's own books and other biology books that may sound similar but are by different scientists.

Given Data / Assumptions:

• The scientist in question is Charles Darwin, a key figure in evolutionary theory.
• The question asks for the specific book in which he proposed his theory.
• Several plausible sounding scientific titles are given as options.

Concept / Approach:
Darwin proposed his theory of evolution by natural selection in his landmark work published in 1859. The widely known and historically important title is "On the Origin of Species". Other titles such as "The Descent of Man" are also by Darwin, but they build on or extend his earlier work. The key is to identify the first major publication that formally introduced the theory.

Step-by-Step Solution:
Step 1: Recall the full classical title, which is often given as "On the Origin of Species by Means of Natural Selection". Step 2: Among the options, "The Origin of Species" clearly matches this historically famous work. Step 3: Recognise that "The Descent of Man" is another book by Darwin that focuses more on human evolution and sexual selection, published later. Step 4: "The Life on Earth", "The Story of the Living World", and "The Families of Flowering Plants" are generic sounding titles and are not the book in which Darwin first proposed his fundamental theory. Step 5: Therefore the correct answer is "The Origin of Species".

Verification / Alternative check:
You can verify this from any standard biology or general science textbook, which always mentions that Darwin published his theory of evolution by natural selection in 1859 in the book "On the Origin of Species". Many exam preparation guides also repeat this fact as a standard memory point for objective questions in biology and general knowledge.

Why Other Options Are Wrong:
"The Descent of Man" is an important later work by Darwin but not the first publication that proposed his general theory of evolution. "The Life on Earth" and "The Story of the Living World" are generic phrases and not classic Darwin titles. "The Families of Flowering Plants" suggests a taxonomy text and does not match Darwin's key evolution book. As the question specifically asks where Darwin proposed his theory, only "The Origin of Species" fits perfectly.

Common Pitfalls:
Students sometimes confuse Darwin's different books, especially "The Origin of Species" and "The Descent of Man". Another common error is to select any title that sounds biological or scientific without recalling whether it is really connected to Darwin. To avoid this, remember that when exams ask about Darwin's theory of evolution, the safest association is with "On the Origin of Species".

Final Answer:
Charles Darwin proposed his theory of evolution by natural selection in the book "The Origin of Species".