It's practically just food for Pokemon that you can make using berries. You can mix the various berries in a Pokemon center.
blocks are exclusive from pokemon diamond,pearl and platinum,so you can't get it. But you can feed pokemon with beries.
Grass blocks in pokemon heart gold are were wild pokemon hide you may catch them and train them or you may beat them with your pokemon and earn exp.
Strength.
Switch Pokemon after every 20 blocks.
You can't.
you can't...
Green!
48.
Which blocks? There's a serious problem with the questions I'm finding on this site.
you have to give it poven or poke-blocks and train it
Safari Zone after unlocking the usage of the blocks.
In emerald you get them in the contest hall by making them with berries.