What limits the rate of photosynthesis?

Light intensity, CO2 concentration and temperature can all limit rate of photosynthesis.
 
For example, if there is lots of CO2 and light but very low temperatures then temperature would be the limiting factor. However, at room temperature on a bright day, CO2 can be the limiting factor instead. So you can see how it depends on the situation.

The answer to this will be from your lab notes/procedure. it would be best to ask another student who participated in the lab as we do not know what was done, what enzyme or if the temperature is celsius or fahrenheit. if i were to guess though i'd say the rate stopped due to enzyme denturing at high temperature

An ecosystem is in a certain area and includes living and non living plus there is weather conditions and a biome is a large amount of area with similar climate.so ecosystem is based on weather and biome is based on the average climate