Before using any chemical in the lab, why should one first read the Material Safety Data Sheet (MSDS)? The MSDS provides information on safe handling of the chemical.
The MSDS explains where the chemical can be purchased.
The MSDS provides the chemical formula for the substance.
The MSDS describes how the chemical will react with other substances.

a "theory" a suggestion that is not 100 % accurate, or a figure. some people say its a theory because they of all the passed theory's about one subject. it depends sometimes theory might be accurate and sometimes they are.

you didn't give any options but heres what i can tell you: an inference is likely to change based on additional observations. the latter is something that you have seen or sensed using your sensory organs while the former is like a conclusion out from what you have observed.

this is more of a statement than a question. is there answers to go along with this, or is it opinion based?