Chloroplasts are the site of photosynthesis in the cell and it also consists of a double membrane. it relates to the solar panels of an amusement park because both things take energy from the sun and use it to provide energy for their systems.
Gravity is not the same thing as magnetism. They are in fact entirely distinct forces. Gravity is a force that works with weight between two objects. Magnetism can pull or separate the two objects, depending on how the magnets point.
As GPP stands for the gross primary productivity, it's the total amount of energy produced in the process and the NPP is the net primary productivity. NPP is the difference between the GPP and the energy used by the producer for the process of respiration.
GPP is a continuous and ongoing process that consumes the energy as compared to the NPP that store energy and not being used. Thus, GPP can affect NPP but NPP does not affect GPP.
For example, GPP is completely being dependent on the chlorophyll content of the plant, but NPP is independent of that content of chlorophyll.