It is released through nitrogen - fixing bacteria
Duchenne muyscular dystrophy is caused by a mutation on the X chromosome, so a male gets it from his mother's X, if she is a carrier. The male child gets a Y and no X from his father, so the disease is always transmitted through the X from the mother. If a female gets Duchenne muscular dystrophy she has to have two X chromosomes, one from a carrier mother and another from from an affected father. This is virtually impossible because most males die before childbearing age and there is no way a female child can get an X from a man who does not live long enough to procreate. About eight percent of carrier women do show some muscle weakness, but they do not have the disease.
A control group is going to be something that you don’t “experiment on or change. It is grown or watched under normal conditions. This way you have a medium to say how things are “supposed” to go.
The experimental group is going to be where you “experiment” and change the normal conditions to see what outcome will occur ( under different conditions then normal )
Exposure to environmental tobacco smoke causes approximately 45 to 46,000 non smokers to die of heat diseases annually. Smoking harms the cardiovascular system in many ways which include; damaging the lining of arteries, reduces HDL, good choresterol, Raises LML, bad cholesterol, increases blood pressure and heart rate, it also causes the platelets to stick together in the blood stream and speeds the development of fatty deposits in the arteries among other risk factors.