How can you tell, GW fluff contradicts itself so many times.. space marines range in descriptiong from 7-10 feet tall.. and apparently it can also vary by marine.. so who knows..
Oh yeah. Well they should have...not...wear...helmet things.
I should write a story about a captured space marine who escapes by dribbling spit onto his bondings then killing the people who captured him with nothing more than his skills, mucles and a big old knife.
please dont.. Most people dont go around capturing space marines.. its not that easy, and IIRC the betchers gland (thing that allows them to secrete acid) does actually have that heavy of an effect, and would have only miminal range/effect, and I believe was actually intended for the purpose you just said, not really for maiming an opponent.. Additionally when you have a chainsword, or powerfist, or powersword.. spitting acid pales by comparison.. that and I dont think it would affect most armors significantly..