Who is “the poor” that is entitled to receive Zakah(obligatory charity)?

The poor is the one who has neither money nor a source of living, or has either of them, but it isn`t sufficient such as being in need for a hundred JDs, and having an income of forty JDs only.

Is it permissible to swear by (Allah ”The Living”)?

Yes, it is permissible because “ The Living “ is one of Allah`s Attributes.

Is it permissible to delay menses by using medication in order to fast Ramadhaan?

It is permissible for a woman to use medication in order to delay her menses so that it becomes lawful for her to fast Ramadhaan, but it is better that she doesn`t do so, and taking the medication is prohibited if she, or her doctors know that it involves a risk on her health.

Is it permissible for a Muslim woman to wear trousers at home?

All Perfect Praise is due to Allah, The Lord of The Worlds 

Is it permissible for the man to put on revealing clothes? Answer: It is impermissible for the man to put on revealing clothes that show his Awrah(private part) which is between his navel and knee, and exercising modesty is better. And Allah Knows Best.