What where three weaknesses of non-European powers that allowed European powers to control or colonize them

Most nations who had been colonized by European powers had lacked the sufficient technology to fend off foes. Some may have had certain equipment of new technology through trade but ultimately the one who is producing the new technology will win over. Great Britain Established there massive Empire with advances in new machinery and medicine. Trains/ steam ships can transport supplies and troops. Automated weapons can mow down hordes of enemies. New medicine can cure diseases found in deep foreign territory (such as Africa).