Nothing really. Primates groom as a social activity most times. Grooming to them is like humans going and hanging out with friends somewhere. Obviously they use it to get clean and look for things in their fur (monkeys) or hair (apes).
If you mean "Are all mammals primates?" then the answer is no. Primates are a type of mammal. All primates are mammals. Not all mammals are primates. For example, cats, dogs, bears, rodents... these are all mammals, but not primates.
Groom means a man that gets married to a bride.
Primates do, to get rid of pests that live in their hair or on their skin. Other animals groom themselves for the same reason, such as cats and dogs.
Fear of primates (MONKEYS)
monkeys groom each other because it builds social life and keeps them healthy and free of disease
a groom
Bride? I'm not sure what you mean, but a bride and groom get married to become husband and wife :)
When you say primates, do You then mean something like cavemen? If You do, I believe that they'll tear it apart in less that two minutes.
Yes, unless by 'primates' you actually mean something that isn't a primate. Primates care for their young, give milk, have advanced brains and sensory organs, and have hair so yes they are mammals, as are humans.
You mean a groom. Try the local agricultural colleges for OND/HND courses, which will include a groom's diploma.
You mean the Groom's Best man? No. The presents are only for the Bride and Groom. Unless the religion/culture hints otherwise. But for Christians, Atheists, Jews and such: Just the Bride and Groom get presents.
All chimpanzees are primates but not all primates are chimpanzees. Humans, for instance, are primates.