The answer is b) "No known sexual mode of spore formation
Carbon dioxide is added to the atmosphere naturally when organisms respire or decompose (decay), carbonate rocks are weathered, forest fires occur, and volcanoes erupt. Carbon dioxide is also added to the atmosphere through human activities, such as the burning of fossil fuels and forests and the production of cement
Error is the amount of imprecision or variation in a set of measurements. It is expressed as a percent error. So the statement is true! Hope this helped!