Is performing Umrah an obligation for who is capable. Is he accountable for not performing it in this case?
                                Umrah is an obligation once in a lifetime for every Muslim. When physical and financial ability is present, it is preferable to perform Umrah, as well as Hajj. If one can afford to perform Umrah but not Hajj, then they should begin with Umrah, especially since Hajj nowadays is not accessible to everyone who wishes to perform it. In contrast, Umrah is more open and easier to undertake. And Allah knows best.
 
 
 
 
 
                             
                        
                            
                                
                                Is it permissible to fast on behalf of the dead who died owing missed fast to make up?
                                His relative should fast on his behalf, and it is permissible for the guardians to give permission to non-relatives of the dead to fast on his behalf as well. And Allah Knows Best.
                             
                        
                            
                                
                                Is it permissible for the woman to use her mobile phone while on the street?
                                All Perfect Praise is due to Allah, The Lord of The Worlds 
Modesty should be observed by the woman at all times, so she is free to use her phone while on the street as long as it is done within the limits of Islamic manners. And Allah The Almigty Knows Best.
                             
                        
                            
                                
                                Is the maternal uncle of one`s mother a Maharam?
                                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.
Mother`s maternal uncle is a mahram. And Allah The Almighty Knows Best.
 
* In Islam, a mahram is a member of one's family with whom marriage would be considered haram, concealment purdah, or concealment of the body with hijab, is not obligatory; and with whom, if he is an adult male, she may be escorted during a journey, although an escort may not be obligatory.