What is considered a woman`s Awrah (parts of the body that must be concealed during prayer) while offering prayer, and is her foot part of it?
A woman`s whole body is considered an Awrah while offering prayer except the hands and the face. Thus, her foot is an Awrah as well. And Allah Knows Best.
A man married a woman at the Islamic Centre in Brussels through a regular marriage contract. However, the husband left her for two years now and never provided her with financial support. Currently, she is staying in Amman, Jordan, and wants to remarry. Is her first marriage considered void and what should she do to remarry lawfully?
All perfect praise be to Allah, the Lord of the Worlds; may His blessings and peace be upon our Prophet Mohammad and upon all his family and companions.
This issue is within the jurisdiction of the Islamic courts and they have the final say regarding the dissolution of the first marriage contract if there is valid ground for that. Therefore, her first marriage remains valid unless a court decision says otherwise. And Allah The Almighty Knows Best.
Is permissible to buy/sell with non-Muslim?
Yes buying/selling for a Muslim with non-Muslim is permissible as regards what is lawful.
Is it permissible for a man to wear transparent clothing?
It is not permissible for a man to wear transparent clothing that reveals his 'Awrah (the area that must be covered). The 'Awrah of a man is "from his navel to his knees", and modesty is more prudent. And Allah Knows Best.