Both photosystems contain many pigments that help collect light energy, as well as a special pair of chlorophyll molecules in the heart (reaction center) of the photosystem. The special pair of photosystem I is called P700, while that of photosystem II is called P680.
The energy pyramid describes decomposers compared to energy lost as heat. Primary producers start at 100% and it decreases to 10% at primary consumers, 1% at secondary, .1% at third level, and .01% at apex.
The biomass pyramid describes the total mass of an organism and as a biomass moves up, the overall mass is losing volume. This means it decreases as it moves from the bottom to the top.
arbon, as with many elements, can arrange its atoms into several different geometries, or "allotropes." In pure diamond, every carbon atom is covalently bonded to exactly 4 other carbon atoms in a very specific and energetically favorable geometry. The diamond cannot be broken or scratched unless many covalent bonds are broken, which is difficult to do. In another common allotrope, graphite, every carbon atom is covalently bonded to only 3 other carbon atoms, and the atoms are arranged in sheets that are not covalently bonded to each other. The sheets can be broken apart easily, ultimately meaning that graphite can be easily scratched. Coal is composed of particles of different allotropes of carbon, and some "amorphous carbon," which has no defined geometry in its atomic structure. Without a continuous network of covalent bonds, coal is easily scratched (i.e. it is not hard).
Chemical composition and physical properties
