9-11/anomalies/questions

• If the towers collapsed due to the weight of the upper floors crashing down on the floors below them, why were those dozen or so upper floors themselves not completely pulverized long before they finished pulverizing the remaining 50+ floors? (Did they have some kind of magical immunity to being pulverized just because they were on top? Oh, sorry, "magical immunity to being pulverized until completely finishing off the bottom floor, at which point they came apart just as they passed street level".)
• What is the explanation for the diagonal cuts found in the steel girders in the wreckage of the twin towers?
• What is the explanation for the molten steel seen pouring out of WTC2 shortly before collapse, and found in huge pools in the debris weeks afterwards -- given that even the NIST admits the fires did not get anywhere near hot enough to melt steel?
• What is the explanation for the thermite and iron globules found in dust from the towers' collapse? ...for the thermite residue found on the steel at Ground Zero?
• What is the explanation for the highly symmetrical and very clean collapse of WTC7, given that NIST claimed it collapsed due to heavy damage on one side (said damage not being visible in any of the evidence publicly available)?
  • And what is the evidence, exactly, which leads the NIST to the belief that there was heavy damage on one side of WTC7? Why hasn't this evidence been released?
• Why was there an explosion in the lobby of WTC7 before either of the twin towers had collapsed?
• How could a civilian aircraft (no IFF signal!) get within striking distance of the Pentagon without being shot down by the Pentagon's ground-to-air defenses?