Questions are WHY we present reasoned arguments.

QUESTIONS identify areas where we need information. The purpose of many scientific studies is to answer a specific research QUESTION, such as whether data or a concept can fill an identified gap in understanding.  Although the overall question of a study may only be asked once (and hopefully answered ;-), the question might be one of the most important aspects of the study! Creating a question that is important, specific and testable could take months or years of dedicated effort, and make or break the feasibility of a research project. 

Questions can also help us to structure our reasoning within scientific communication. For example, it can be helpful to predicate each argument that we make with a question that answers WHY we are making the argument. The questions that motivate arguments are often implicit (unstated), but one way of structuring arguments is to specify our questions explicitly, by clearly stating the question that motivates the argument at the beginning.

Although questions can be important and helpful, we can't communicate clearly simply by asking questions -- we have to answer them! Questions need conclusions. To move our understanding forward, we must answer our questions by using evidence to defend conclusions.

Conclusions are NECESSARY OUTCOMES of reasoned arguments.

"CONCLUSION" has two common meanings. First, a conclusion is the outcome of an argument (which could involve judgment). Second, a conclusion often refers to finality, or ending. The two meanings of "conclusion" are consistent with each other because  the outcome typically comes at the end of an argument.

Having a strong CONCLUSION is the MOST IMPORTANT part of a scientific argument. Therefore, it is important to make sure that the conclusions at each level of organizations of scientific communication (e.g. paragraphs, sections, or overall papers) are clear and strong.

What makes a strong conclusion?

Strong conclusions are simple and specific. For example:

"We reject our measurable hypothesis that students who drink 8 ounces of coffee will have significantly greater sprint performance than students who do not drink coffee."

Conclusions can motivate and initiate arguments.

In addition to clearly stating the outcome of an argument, conclusions have an additional role. Having evidence sufficient to support a conclusion is typically what motivates the process of presenting a scientific argument -- the conclusion can lead to the question. When scientists are confident that their evidence supports a conclusion, the scientists can clearly articulate their research question and begin the process of presenting their research. 

Scientific conclusions often perform the function that "claims" serve in more general argumentation frameworks (Toulmin, 1958). Arriving at a reasonable conclusion allows scientists to make a "claim," and begin of the process of constructing written arguments that communicate scientific findings. Some educational frameworks even directly apply the terminology of "claims" to scientific contexts (McNeill, 2008). However, the word "claim" connotes statements that can be made without evidence (e.g. Oxford Living Dictionary). In contrast, conclusions require supporting evidence. "Claims" that remain tentative are commonly termed scientific "hypotheses." However, even hypotheses are typically derived from extensive theoretical or empirical evidence. Therefore, scientists do not commonly use the word "claim" to refer either to questions, hypotheses or conclusions.

The process of questions leading to conclusions (and vice versa) is a more specific representation of scientific argument that the more vague term, "claim."

Clearly-stated questions can motivate scientific arguments, and conclusions culminate scientific arguments. Therefore, using questions or conclusions as topic sentences (at the beginning of arguments) and conclusions as outcomes (at the end of arguments) can help structure understandable and persuasive reasoning.

Strong reasoned arguments begin with clear QUESTIONS AND END WITH WELL-SUPPORTED CONCLUSIONS. Determining the conclusion of an argument before writing can HELP ESTABLISH A GOAL TO GUIDE REASONING.