Final answer:
The guidelines modified in 2010 could pertain to a range of subjects; without more context, it's not possible to identify the three main parts specifically.
Step-by-step explanation:
The guidelines that were modified in 2010 may refer to a wide variety of subjects, including but not limited to health regulations, environmental standards, or educational policies. Without more context, it is not possible to provide the specifics of the three main parts of the guidelines. For instance, the modification mentioned about the 2008 ozone (03) standards could suggest an environmental subject, where the final rule signed on October 1, 2015, became effective on December 28, 2015. Similarly, mentioning a three-part process in a calculation could relate to mathematics or chemistry, often involving stoichiometry or unit conversions.
Without additional context, these examples could refer to a number of significant national policy changes in various fields that comprise three main components, as suggested by the provided excerpts. One might deduce that these guidelines encompass maintaining a balance in some kind of system, whether biological, environmental, or computational.