Answer:
The correct answer is D. Reduced levels of circulating estrogens.
Explanation:
Estrogens prevent the loss of calcium and ensure its proper mineralization, thus preventing the bones from becoming brittle, maintaining the consistency of the skeleton and preventing osteoporosis. Osteoporosis is a skeletal disease in which there is a decrease in bone mass density. Thus, the bones become more porous, the number and size of the cavities or cells that exist inside them increases, they are more fragile, they resist shocks worse and they break more easily. Menopause is the definitive cessation of ovarian function that, externally, results in the disappearance of the menses and usually occurs around 50 years (the interval goes from 45 to 55 years). It is the gradual loss of calcium in the bones, which accelerates in the first years of menopause due to estrogen deficiency. At the beginning of the disease, there are no symptoms and, as it progresses, there is a tendency to suffer fractures, which leads to a decrease in height.
The more polar A compound moves ahead of the less polar B compound.
Explanation:
The analytical process that involves the separation of colored substance or chemicals is named as paper chromatography, a replacement of thin-layer chromatography. In this method, there is the use of two solvents and rotation of paper at 
. It helps in isolating two complex compounds of equal polarity.
A non-polar mixture of solvent is required in the mobile phase of this method. In accordance with the retention factor of this process, the more polar compound A will go further than compound B as the solvent is non-polar.
Cyanobacteria were very simple organisms and performed were an role in changing Earth's early atmosphere. They carried out photosynthesis to produce the materials they needed to grow. In this process, they release Oxygen which is needed to sustain life on Earth for Humans and other organisms.
