Forum:Three questions

Hi, got three different questions. Firstly, do all the reaper systems/standard systems have 'discoveries' to make? In most systems I've found 100% of the things, like war assets, creditors or fuel, but in a fuel I can't detect any anomalies so I was wondering if they don’t actually have any. In one on my ME2 play through I accidently triggered the end game by attempting a mission from which there was no going back, as in I could no longer go about the galaxy as I pleased after I had done this mission. Is there such a mission on ME3 so I can avoid doing it until I am ready to finish the game? What is the difference between war readiness and effective war readiness? My effective seems to be about half my total but I'm not sure why. Also, how do I improve my galactic readiness rating? is this tied to the multiplayer? Thanks.