in question number 6, the correct answer is false. this is because arrow C is representing a combustion reaction whereby hydrocarbon or organic carbon from the fossil fuel is burnt in the presence of oxygen to produce carbon dioxide. this process is not conversion of chemical energy to mechanical energy. in this process energy will still be stored in form of chemical energy in the bonds of carbon dioxide and water produce
in the question number 7 the correct answer is true. this is because the green plant is using energy from the such for the process of photosynthesis. photosynthesis is a process by which green plants make their own food using energy from the light. light energy is used to split the molecules of water to oxygen and hydrogen ions. oxygen is released into the atmosphere whereas hydrogen ions are used in the dark stage of photosynthesis a process referred to as carbon fixation. the end result of carbon fixation is production of organic compounds such as glucose, protein and lipids among others. these foods store energy in form of chemical energy. so arrow A represents transfer of solar energy to chemical energy
in the question number 8, the arrows that represent the release of carbon dioxide include arrow C and arrow F. in arrow C the process occurring is referred to as combustion and it occurs when hydrocarbon in fossil fuels reaction with oxygen in the presence of heat to produce carbon dioxide and water. the arrow F represents respiration, a process by which living cells manufacture energy in form of ATP from organic food such as glucose. respiration end products include water carbon dioxide and ATP. it is essentially the reverse of photosynthesis
in question number 9, arrow E represents cycling of carbon from living organisms to non-living organisms. this is because it is showing conversion of a carbon from the dead tree to fossil fuel. when plants and animals die and buried deep in the ground, they are slowly converted to fossil fuels which contain organic hydrocarbon compounds including petrol, kerosene and other compounds.
in question number 10, arrow B & C show the conservation of energy and mass. when living organisms die they are converted to fossil fuels which are used in industries to produce energy required for various activities. during this process carbon dioxide is released into the atmosphere and it is used by plants in the process of photosynthesis as shown by B. this is conservation of energy and mass the number of carbon in the fossils fuel initially came from living plants and when fossil fuel is combusted it produces carbon dioxide that will be used in the process of photosynthesis and cycle continues.
