Part 1: The carbon-monoxide, carbon-dioxide, and other harmful gasses are being released into the environment by the factory causing the air to be polluted.
Part 2: The factory is putting in mechanical work, so the energy coming out is mechanical energy which is being transformed into chemical energy in the form of harmful gases.
Part 3: This process is a recycling of carbon in the carbon cycle because along with adding carbon-dioxide to the air, it also provides photosynthetic autotrophs with carbon-dioxide which is required for photosynthesis. This will then be turned into oxygen which is used for cellular respiration in animals.
Explanation: The definition of mutualism states " interaction between two or more species where each species has a benefit". The bird is getting food from the insects and the horse is getting the insects removed. Both are benefited.
