[BigFire]

Originally Posted by Yebyosh

You're welcome, though you should thank ElvenPower instead for its his/her suggestion.

Now let me speculate for you

On question 2 (about Al & the Truth).

Spoiler:

Not really. You have to see the Truth and understand it. We are still unsure if Al understood the Truth. Recall his answer to Izumi's question of "One is what, what is one?" (not exact, need to go back and get the exact quote). His seem to be the "good enough" answer but Ed's answer was the true answer.

Lastly, you use your body to form the structural(alchemical) matrix. The human body with its complex compounds and structures enable Ed & Izumi to do almost any alchemy with ease. Al has a metallic body. He could at best perform limited alchemy without using sigils.

Even more Spoiler about the Truth

Spoiler:

More specificially, Ed ask al whether he saw the "Thing" immediately after he got fitted with automail. Al plainly don't know what Ed's talking about. Thus far the only two people who can use their own body to form structural matrix with their own body both managed to lost something significant. Ed lost his left feet before he saw the truth. He than uses his new found power to bind his brother's soul to the armor at the cost of his right arm. We're not sure who Izumi Curtis tried to bring back (I'm guessing a still born baby), but I'm speculating that it has cause her to be physically frail (caughing up buckets of blood at the most comical time).

Though as we saw at the end of Chapter 31, Al didn't remember the moment he was rescued by Ed until the Chimera's blood touched his seal, so he might have glimpse at The Truth, and not understand it (Ed most certaintly did).