You answered it. It says a=5
A structure made up of two or more kinds of tissues that perform a special functions is an organ.
Coal mining causes massive land use, tailings (waste), pollution to the air and water, and the effects it can have on the workers mainly includes respiratory problems.
Some things that could happen to prevent pollution is to keep the area as contained as possible away from water outlets. Safer, environmentally friendly chemicals could be used instead of chemicals that pollute the air and water. Mining waste needs to also be properly disposed of and away from any water is could seep into.
