Several words can indicate the conclusions of reasoned arguments.
CONCLUSIONS are the most important parts of reasoned arguments (i.e. see the CONCLUSIONS section).
There are several Logical Transitions that indicate conclusions, including:
As a result
To this end
Although there are several words that indicate conclusions, it is NOT necessary to use different terms to conclude each reasoned argument that you make. Avoiding repetition is far less important than clarity in scientific writing. Therefore, it is acceptable to use the same word to indicate the conclusion of many or all of your arguments.