>>2
I found the answer long before you replied, by googling the question rather than the topic. Of the first ten results from the google link you supplied, none directly answer the question. The user manual doesn't address this issue until page 51! Please do more research before contributing to a thread and be sure that your answer is useful -- adding complexity to a simple issue makes you an enemy of education. You should read the SICP chapter on Abstraction as it directly relates to this issue.
For newcomers, C-m-z will execute the expression in the current region (control-alt-z on PC).