Answer:
3: if your calling a human any one of those animal names you are insulting them. these animal names have a negative connotation when they are compared to human beings. For instance if u call a person a rat, it means they are untrustworthy. A pig a derogatory term for an unclean person.
4: dog goes "bark" rooster goes "kaka doodle doo" bird goes "chirp" frog goes "glump" these sounds are the onomatopoeia. hope this helps!