complete,complain,computer,
No, "com" is not a prefix. It is a standalone word that can function as a prefix or a root in certain contexts, but it is not considered a standard prefix in English.
complete competition competitor
'Com-' is a prefix, in words such as 'complete', 'completion' and numerous others.
computer
complicated,computer and community.
Com means "with" or "together," and these words do add the prefix to existing words: compassion, compromise, commission, compadre, community, commingle, commotion.
duet
See the related link for a list with OVER 1,500 words starting with the prefix IN.
Combat, comedy, comets, comics, coming, commas, commit, common, compel and comply are words. They begin with the prefix com.
Yes, spec is a prefix. See the related question for a list of words beginning with this prefix.
compress,combine,compatible,compact,commity,commitment
Bio- means life......and some words areBiologyBiographyBio hazard