
Study the given molecular structure of double-stranded polynucleotide chain of DNA and answer the questions that follow. 
(a) How many phosphodiester bonds are present in the given double-stranded polynucleotide chain?
(b) How many base pairs are there in each helical turn of double helix structure of DNA? Also write the distance between a base pair in a helix.
(c) In addition to H-bonds, what confers additional stability to the helical structure of DNA?
The female reproductive system provides various functions. The ovaries produce the egg cells known as the ova or oocytes. The oocytes are then taken to the fallopian tube where fertilization by a sperm may occur. The fertilized egg is then transferred to the uterus, where the uterine lining has thickened in regard to the normal hormones of the reproductive cycle. Once in the uterus, the fertilized egg can implant into the thickened uterine lining and continues to develop. If implantation does not take place, the uterine lining is shed as menstrual flow. In addition, the female reproductive system produces female sex hormones that preserve the reproductive cycle.
During menopause, the female reproductive system slowly stops making the female hormones that are required for the reproductive cycle work. At this stage, menstrual cycles can become irregular and finally stops. One year after menstrual cycles pause, the woman is deemed to be menopausal.