1st part
Good morning. Yes, it's non-controversial that biological life begins at conception. But while many believe that where there is human biological life there must be a human soul, the Church, in her magisterial statements, continues to preserve a distinction between the two. It's theologically important that she do so. 

The Church's main arguments against abortion are: 1st, moral caution - the soul might be present, and so it might be murder. 2nd, equivalence - if the soul isn't present, it soon will be, so abortion is equivalent to murder, soul or no. 3rd, the conceptus is a biologically human life, and there's a commandment against taking human life.