The AMCAS application consists of a maximum of fifteen work/activity descriptions, all of which must be maintained within a 1325 character requirement (including spaces). Do not fall into the trap of trying to fill the space. A brief, streamlined AMCAS is much more likely to be read - not scanned.
Imagine yourself as an admissions committee member who has scores - maybe hundreds - of AMCAS to review. You start to review an AMCAS that fills all of the allotted space. You are not going to look upon this favorably! You are seeking well-written, brief summaries of applicants' accomplishments.
For help with your AMCAS descriptors please contact me. Showcasing your accomplishments optimally is essential.