I'm sure this is a reflection of being new to the game, but... I'm trying to replace an old light fixture with a new one. I've taken the old fixture down, but there is no ground wire coming out of the box, only a black and white. What do I connect the ground wire in the new fixture to? Thanks

You were very helpful with my last posting, and I'm feeling like I can take on the next project, but I'm nervous. I'm replacing a single bulb light fixture in the hallway with a two-bulb fixture. Two questions: 1) The new fixture has two sets of wires (actually, 2 pairs of black and white and one single ground wire.) Do I now connect all three whites in one wire connector and all three blacks in one? 2) A little slip of paper in the new fixture's box says that I should use wire rated at least 90 degrees. My house was built in the late 30s. I think I remember it only being rated at 60 degrees. How do I proceed? THanks