A trade bloc is a type of intergovernmental agreement for a group of countries where barriers to trade are reduced or eliminated among the participating states and less competition and for economic integration.
The multiplier effect means that "An effect in economics in which an increase in spending produces an increase in national income and consumption greater than the initial amount spent."
Photosynthesis is the process that takes place in leaves that converts light energy into chemical energy or sugars. It occurs in the presence of chlorophyll that is present in leaves as a green pigment, carbondi oxide and water with the help of sun light. So the energy for photosynthesis come from sun light.