Question

Chemical theory of the origin of life was given by
A. Stanley Miller
B. Oparin and Haldane
C. Louis Pasteur
D. Spallanzani

Answer 1

Hint: Chemical theory of the origin of life is related to the chemical evolution. The term chemical evolution refers to the formation of complex organic molecules from simple inorganic compounds by the chemical reactions that occurred in the ocean in the early history of life. Chemical evolution is considered the first step in the development of life on Earth.

Complete answer: The name chemical theory of the origin of life itself says that life on the planet Earth was first formed through chemical evolution. Chemical evolution involves chemical reactions of inorganic compounds to form organic compounds. In the year 1992, Haldane and Oparin proposed the chemical theory of origin of life in which he stated that formation of organic materials take place from abiogenic material in presence of an external source of energy. They also stated that the first form of life could have come from prebiotic life. The most important point of the theory which should be considered is that the first life was formed in the ocean. During the early times of life, earthquake and volcanic eruptions were so common which led to the decrease in atmospheric oxygen. So, it is considered that the first life formed on the planet Earth was anaerobic and formed in the Ocean.
So, option B is the correct option.

Note: The chemical evolution period did not last more than a billion years. Oparin’s theory is also called artificial synthetic theory due to the fact that it is based on the artificial synthesis of the pre-existing organic molecules. Later in the year 1953, Harold C. Urey and Stanley Miller experimented with Oparin and Haldane theory and successfully produced organic compounds from the inorganic compounds which were thought to be pre-existing on Earth.