I don't know if their is sopposed to be options but my best educated guess is "Natural"
Answer:
legth of life is the answer
Nitrofurantoin is an antibiotic drug that used for treating urinary tract infection. This drug is relatively safe but has toxicity to some organ such as liver, nervous and lungs.
Prior lab work will exclude the chance that the organ is damaged before treatment. It also can be used to monitor if there are major adverse effect happens to the patient.
The correct answer is option B. Higher levels of haemoglobin
A higher level of the haemoglobin allows the organism to survive in low oxygen condition. The low oxygen level decreases the amount of oxygen delivered to the cells, to cope up this condition, there is an increase in the haemoglobin content. The increased haemoglobin concentration allows the delivery of the sufficient amount of oxygen, as the number of haemoglobin increase, the capacity of oxygen carried to the cell is increased.