Which do you think is more thermodynamically stable? a linear polysaccharide made of random sequences of different hexose monomers (glucose, galactose, mannose, etc. - heteroisomers) or one made from only one type of isomer (homoisomers)?

one made from only one type of isomer (homoisomers)

Explanation:

Polymers made up of one isomer i.e. homo isomers are more Thermo dynamically  stable than the those are made of different monomers.  The reason being the bonding between similar kind of molecules are much stronger and hence are difficult to  break at low temperature,

whereas the polysaccharide made of random sequences of different hexose monomers are less stable on heating because their bonding not so strong.