Couple "Noob" Questions - New Player Here

Kinda new at AoE2. Been playing it quite a bit and I can definitely see why this game is held to very high esteem. I am loving it! I am patiently waiting for DE to come out, but until then, I am playing HD. I just have a couple questions that I am hoping someone in this community can answer.

​

1. I've seen it somewhere, and I am not for sure if it is a specific civ tech or if everyone has it, but where is the tech to make your infantry stronger against buildings? This for all civs or some?

​

2) I have made siege weapons, but I notice that every time my opponent comes at me with theirs, their boulders are on fire? Where is the tech to upgrade my Siege weapons to fire based ones? I am assuming this increases the damage?Is this tech civ specific too?

​

Thanks guys! My brother and I have been playing with each other online and we are both loving this game. Crazy how a 19 year old game has not only stood the test of time but is still bringing new players in! I love it and hopefully in a few months I can somewhat be a challenge to you online! ;)