What's the difference between 'Ya' & 'Al'(e.g. Ya-Rashidu / Al-Rashidu) & the difference between messengers,prophets,Imams and a Caliphs?

1. 'Yaa' is a letter of calling or addressing, e.g. you say 'Oh' so and so.%0D%0ASo, if 'Yaa' comes before a name or person, it will mean calling or%0D%0Aaddressing him, e.g. al-Rajul means the man and 'Yaa Rajul' means 'O man'.%0D%0AMessengers and prophets (Alayhis salaam) are chosen people by Allah Ta'ala%0D%0Aand are sinless servants of Allah. A nabi (Alayhis salaam) is he who follows%0D%0Athe messengers before him and a Rasul is sent with his own book and new%0D%0Alaws, e.g. Tawraat, Injeel, etc.%0D%0AIn the English terminology, as commonly used nowadays, both messengers and%0D%0Aprophets are synonymous to each other. However, in the strict Arabic%0D%0Aterminology, there is a difference between Rasool and Nabi as explained%0D%0Aabove. Imam refers to a leader and Caliph also has a similar meaning%0D%0Aalthough it is generally referred to those special leaders who were in%0D%0Acharge of the affairs of Muslims after the demise of Nabi (Sallallaahu%0D%0AAlayhi Wasallam), e.g. Hadhrat Ali, Mu'aawiya, Haaroon, etc.%0D%0A2. Aadam (Alayhis salaam) got sick for 11 days, thereafter, he passed away.%0D%0AHe was buried in a cave in mountain of Abi Qubays. (Taarikh Islam)%0D%0A3. Allah Ta'ala has created men and women differently and given them%0D%0Adifferent roles and duties to perform. We do not need to know the wisdom%0D%0Abehind Allah Ta'ala's actions. He is All-Knowing, All-Wise. Kindly refer%0D%0Aattached%0D%0A4. Satan is cursed by Allah Ta'ala and will burn in the fire forever with%0D%0Athe rest of the disbelievers.%0D%0A5. In the time of Rasulullah (Sallallaahu Alayhi Wasallam), the disbelievers%0D%0Aasked Rasulullah (Sallallaahu Alayhi Wasallam) for a sign of his%0D%0Aprophethood. So, Rasulullah (Sallallaahu Alayhi Wasallam) with the help of%0D%0AAllah Ta'ala showed them the splitting of the moon into two parts until.%0D%0AThereafter, it came back to normal. This sign of Qiyaamat has already%0D%0Apassed. The incident took place in Makkah before migration to Madina.%0D%0A(Jaamiul Bayaan vol.13 pg.98)%0D%0A%0D%0Aand Allah Ta'ala Knows Best%0D%0A%0D%0AMufti Ebrahim Desai