Suppose that, for every two photons of light striking photosystem II (see the Light Reactions tutorial), one ATP molecule is produced at ATP synthase. The ATP then goes to the Calvin cycle and participates in PGAL synthesis; two PGALs combine to form one glucose molecule. Considering the assumptions above, how many photons of light must strike photosystem II to generate the ATP necessary to produce one glucose molecule in the Calvin cycle?

Match each law or principle to its description. 1. law of original horizontality sediment continues to spread in a flat plane until it hits an edge or runs out of material. 2. law of superposition the youngest strata are at the top and the oldest are at the bottom. 3. law of original lateral continuity sediment gets pulled down by gravity in a horizontal and flat layer. 4. law of cross-cutting or intrusive relationships if there is a fracture or intrusive feature seen in rock strata, it is younger than the rock strata.