As part of a delicately balanced system, the human heart secretes a hormone, a substance that controls the amount of salt in the blood and the volume of blood circulating within the body. Only very small quantities of the hormone are required. This hormone is extremely important in regulating blood pressure and is found in large amounts in the blood of those suffering a heart attack.
If the statements above are true, then it must also be true that
A．if there is a deficiency in the amount of heart hormone secreted, low blood pressure will result.
B．it is large quantities of the heart hormone that cause heart attacks to occur.
C．the effects of a small amount of the heart hormone will be long-lasting in the body.
D．if a device that is only a mechanical pump is used as an artificial heart, it will not perform all the functions of the human heart.
E．(E) any drug that regulates blood pressure will have its effect by influencing the amount of the heart hormone secreted.
