Yes, a dog can have as many as 15 different siblings and never know them.
Depends on what you mean by "can". Physically they certainly can, but they shouldn't be allowed to. If they have the same parents it doesn't matter if they're from different litters, they're still brother and sister. And breeding from such close relatives just isn't healthy.
Yes, they can.
If they are from different parents then they are not called brothers or sisters, but if they are from different parents then I suggest it's not allowed.
no one because they have different names and two because they have different parents.
Your sister-in-law is either the sister of your spouse or the wife of your brother. The parents of the sister of your spouse are also the parents of your spouse and so are your mother-in-law and father-in-law. The parents of the wife of your brother are not related to you.
When your parents have a brother, or sister.
Your half-brother's half-sister could be your full sister, or not related to you at all. For example, say your parents are Joe and Mary and your half-brother's parents are Mary and Steven. Say your half-brother's half-sister is Barbara. If Joe and Mary are Barbara's parents, then she is your full sister and your half-brother's half-sister. If Barbara's parents are Steven and Jane, then Barbara is not related to you (unless there is an adoption).
An uncle is the brother of one of your parents, or the husband of the sister of one of your parents. A nephew is the son of your sister or brother.
A brother and a sister, both being children of the same parents, are siblings.
Your uncle is the brother of one of your parents or the husband of the sister of one of your parents. Your aunt is the sister of one of your parents or the wife of the brother of one of your parents. You are their niece (if you are a girl) or nephew (if you are a boy).
Parents never tell my little sister/brother and her mates off when they are annoying me because parents either feel embarrased to shout at your little sister/brother in front of her friend or that they feel guilty telling off your little sister/brother's friend, what you have to do is tell your parents what your little sister and her friend did and hopefully they will tell your little sister/brother off for doing so, that's what happens when my little sister annoys me
yourself