Parkinson's disease often involves the degeneration of neurons that produce , which are located in a brain area called the .

an active site is a region that is present on an enzyme where the reactants or the substrate molecules we can say bind and experience a chemical reaction. the substrate is basically a reactant whose concentration is changing and that is converting into a product after binding at the active site of an enzyme

if your own plato the answer is b. the fern transitioned from sporophyte generation to gametophyte generation.

the endomembrane system i think