You're either talking about Community which means grouping of different organs or population which is the grouping of the same organ
<u><em>Photosystem I</em></u> is found in the membrane facing the inside of the grana and <u><em>Photosystem II</em></u> is found in membrane facing the stroma
Air and pressure cause metamorphic. Igneous is magma and water
A population is a group of individuals living IN THE SAME GEOGRAPHICAL AREA that are capable of interbreeding and producing viable fertile offspring.
The cell has to use active transport when it's trying to transport material against the concentration gradient. (from low to high concentration) Or, if a molecule is too big to diffuse through the cell membrane, it must be moved through using a carrier protein.
Hope that helped you.