Is it permissible to offer mandatory prayer while sitting?
All perfect praise be to Allah, The Lord of The Worlds, and may His Peace and Blessings be upon our Prophet Muhammad and upon all of his family and companions. Standing up is a pillar in the mandatory prayer and the prayer is not valid without it unless one cannot do it. As for Nafila (supererogatory prayer), one can perform it in the state of sitting even if he/she can stand, but his/her reward is half the reward of the person who prays while standing if he/sh has no legal excuse for such an act. And Allah Knows Best.
Who is obligated to fast?
The one obligated to fast is the Muslim who is of sound mind, mature, capable of fasting, and free from obstacles such as menstruation or postpartum bleeding. And Allah Knows Best.
Is it permissible to trim the eyebrows if they become excessively long?
Trimming eyebrows is permissible if they become excessively long, yet; it is reprehensible. And Allah Knows Best.
A Christian woman wants to marry a Muslim man through an unregistered marriage contract and for a specific period because of certain circumstances. She is an adult and wants to know the correct procedure so as not to make any mistakes. What is the correct thing to do in this regard?
All perfect praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
Every marriage should be conducted through court in order to preserve the rights of the spouses and avoid any accusations. In fact, a person shouldn`t be ashamed of what is lawful. Rather, he/she should overcome those circumstances and start in the correct way. And Allah The Almighty Knows Best.