If aliens wanted to create new human pet breeds using only selective breeding, what traits would they find easiest or hardest to alter and what kind of timescales would be involved? Would we be easier or more difficult to breed selectively than, say, dogs?Gerry Walsh, Maynooth, Kildare, Ireland
Is there somewhere in the body that can store fluid, apart from the bladder? Most nights I wake to empty my bladder after exactly 4 hours sleep, but on occasional nights where I haven’t been to the loo all day previously I have to get up three of four times instead of only once. It’s obvious that the urine has been building up during the day, but it wasn’t here in my bladder before I went to bed. So where was it?Virginia Love, Ormond, Victoria, Australia