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.
Some genetic mutations can be completely harmless, while others are life-altering. Mutations happen when DNA is copied incorrectly. This causes an irregularity in the DNA. Mutations are permanent changes to genetic material that can be passed on to offspring. These changes happen randomly and can occur in any type of gene. While some mutations are not harmful (hazel eyes, for example), many mutations have harmful effects on health.