Osteoporosis is a disease characterized by a deterioration of bone tissue which causes an interference in bone microarchitecture and a subsequent susceptibility to fractures. The causes of the disease are obscure and the medications used in its treatment can only slow bone loss without rebuilding bone tissue. In women, osteoporosis often occurs after a sharp drop in estrogen production, but women are also diagnosed with this disease before the onset of menopause. Although osteoporosis is often associated with elderly women, it is also common among people with certain hormonal disorders or users of glucocorticoids. Fractures are most common in the vertebral column, the pelvis and the carpals, although they are possible in any bone in the body.
Recently, a new theory has emerged which offers an explanation of bone formation and of the bone loss associated with osteoporosis. According to this theory, osteoporosis can be linked to a mutation of gene LRP5. Gene LRP5 controls serotonin production in the gut, a completely separate mechanism from the serotonin produced in the brain. The more serotonin the gut produces, the more inhibited the growth of bone cells.
Important yet inconclusive experimental support for this theory comes from laboratory experiments with mice. Scientists deactivated the LRP5 gene in the DNA of mice, which caused the bone-forming cells to degenerate. However, the same cells were then examined in the laboratory where, without any exposure to serotonin, they developed normally. Unfortunately, human patients suffering from osteoporosis did not have an abnormal amount of serotonin in their blood.
The second paragraph performs which of the following functions in the passage?
A) It resolves a problem presented in the first paragraph.
B) It presents a theory which is negated in the third paragraph.
C) It connects a problem raised in the first paragraph with a solution offered in the third paragraph.
D) It offers a theory which is explained further in the third paragraph.
E) It presents a possible solution for a problem presented in the first paragraph.
Pls explain your pick.
Why the author uses the term 'unfortunately' in the last sentence of the passage?
Recently, a new theory has emerged which offers an explanation of bone formation and of the bone loss associated with osteoporosis. According to this theory, osteoporosis can be linked to a mutation of gene LRP5. Gene LRP5 controls serotonin production in the gut, a completely separate mechanism from the serotonin produced in the brain. The more serotonin the gut produces, the more inhibited the growth of bone cells.
Important yet inconclusive experimental support for this theory comes from laboratory experiments with mice. Scientists deactivated the LRP5 gene in the DNA of mice, which caused the bone-forming cells to degenerate. However, the same cells were then examined in the laboratory where, without any exposure to serotonin, they developed normally. Unfortunately, human patients suffering from osteoporosis did not have an abnormal amount of serotonin in their blood.
The second paragraph performs which of the following functions in the passage?
A) It resolves a problem presented in the first paragraph.
B) It presents a theory which is negated in the third paragraph.
C) It connects a problem raised in the first paragraph with a solution offered in the third paragraph.
D) It offers a theory which is explained further in the third paragraph.
E) It presents a possible solution for a problem presented in the first paragraph.
Pls explain your pick.
Why the author uses the term 'unfortunately' in the last sentence of the passage?
....hahahaa
