biff needs help!

[sam_no3]

haven't really got much knowledge on cars but wondering what the circled bit in the pic below is. I've stuck my hand over the gap and and can feel air blowing out i think if i rev the engine, sure theres a really basic answer, thought it might be the intake for the air filter but it looks like it wouldnt get a lot of air through.

Another seperate question just out of curiosity, if i suddenly rev the engine from idle theres like a little plunger thing on top of the engine which opens (or closes?) this is the roughly in ther blue circle in the pic, not too fussed about it but im just curious, if i rev the engine slowly it doesnt open (close?)

any help if really appreciated, ta!

Edit: can't seem to be able to upload the picture. Basically the bit in the red circle is the black intakey bit right at the front, sort of has a gap on the left hand side and connects to the air filter box.