By the layers of sediments
Think about the formula for photosynthesis, (CO2 + H2O = C6H12O6 + O2) and explain like you would to a five year old. Ex. When you add carbon dioxide and oxygen...
Temperature affects the type of plants because different plants require different temperatures and precipitation levels. Such as in the case of cacti, they need very little precipitation and can withstand very high levels of heat.
Yes, it can bind to an intracellular receptor.
