The first one, many neurons invariably die, and virtually all memories decay as a result of this. It's simply not in our bioogy to "remember everything", not until neurons become immortal. My guess is the author of this was into pop psychology.

I'll admit I caught the next one because of an episode of house, but you are not a completely new person every seven years. The AVERAGE cell is recycled that fast, but some cells, like neurons, stick around for much longer.

The "body reacts at 170 mph" doesn't really make any sense. Reactions should be measured as acceleration, perhaps it means mph/s? Does it mean a specific reflex, and obtain "MPH" by calculating distance reflex made you move by time?

To hair being virtually indestructable, that doesn't really make any sense either. Any "piece" of hair could be easily destroyed. If you mean at the molecular bonding level, then the same could be said of a lot of things, and plastic would be several orders of magnitude more indestructable.