Is Iddah (waiting period) incumbent on an old woman whose husband had died?

Upon the death of the husband, Iddah is incumbent on the wife regardless of their age. And Allah Knows Best.

What is the ruling on the existence of cattles' marketplace of (Sheeps, cows and chickens ) inside a graveyard?

Graves must be respected, and it is not permissible to sit on them or show any disrespect. Establishing a marketplace within a cemetery is undoubtedly a form of disrespect to the deceased and is not permissible. Such actions should not be tolerated. And Allah Knows Best.

I am pregnant with four twins since two months although I didn't have childbearing potential during the last four years. In addition, the doctor specialized in reprusccusions, already has notified me about the possible reprusccusions as a result of being pregnant with four twins as follows: abortion, Metrorrhagia, Premature birth, high blood pressure, gestational diabetes and the like. What is the ruling on aborting some of the aforementioned embryos? A medical report was attached in which the status of my question is clarified.

Is it permissible to make up missed prayers at the times in which praying is disliked?

All perfect praise be to Allah,The Lord of The Worlds                                                                                                                                                                        It is permissible to make up missed prayers at any time even that in which praying is disliked. Absolute supererogatory prayer is forbidden to be performed at the times in which praying is disliked, and this also applies to Ihram and Istikhara prayers. However, there is no harm in offering prayers in Mekah during those times. And Allah Knows Best.