Yes. She is your sister through your brother or sister.
a cow
Yes, your husband is considered to be your closest relative.
Yes, a cousin-in-law is considered a relative by marriage, not by blood.
Before or after a divorce a step-sister is not considered a legal relative in most jurisdictions.
SHe's your relative by virtue of her sister being married to your brother.
If by "stepson" you mean someone who was legally adopted into the family - yes, they are a legal relative. However, they are NOT considered to be a "blood" relative.
Yes, your wife is a relative by marriage, and is considered to be your closest relative.
Yes, she is your sister-in-law.
A relative's business address
The phylum Chordata is considered to be the closest relative to humans. Within Chordata, the subphylum Vertebrata, which includes animals with a backbone, is the most closely related to humans.
If they have a biological relative then no, a brother is a closer relative than an adoptive father is. Legally though, if you are the only guardian/ relative then you will be next of kin.
Yes, a father-in-law is considered mahram in Islam, meaning that they are considered a close relative and are not permissible to marry.