2
1
Yes. Each sets of parents has to give consent for their child.
tetrad
3 sets
Depends. Some children who have contact with both they're biological and adoptive parents refer to both sets as "mom & dad". So I would talk to both sets and ask what they feel comfortable as to what you should call you're biological parents.
there are 23 sets
Inbreeding
Yes - especially if BOTH sets of parents are dead.
Inbreeding!
two sets of wings
Three sets
how many sets of parallel lines are in a triangle