Genes" is the one among the following choices given in the question that we call these units of hereditary information today. The correct option among all the options that are given in the question is the first option. I hope that this is the answer that you were looking for and the answer has actually come to your desired help.
The term is called a theory.
In scientific investigation, a theory is a well substantiated explanation of how a particular phenomenon works based on the set of facts which had been repeatedly confirmed through observations and experiments. A scientific theory gives reliable account of a phenomenon.
In this question in which is the major source then of free oxygen in the earth's Proterozoic atmosphere is being produce by the evaporation of the ocean water. Hope this answer would be of big help to this assignment then.
Chloroplasts are the organelles that contain the chlorophyll pigment, which is essential for the good-making process of photosynthesis.