Answer::: Brain structures called the hypothalamus and pituitary gland control the menstrual cycle. The hypothalamus triggers the pituitary gland to make hormones that trigger the ovaries to make oestrogen and progesterone. ... Disorders of the hypothalamus, pituitary gland or ovaries can affect menstruation, causing amenorrhoea
Errors can occur when the chromosomes segregate into the gametes during meiosis resulting in egg or sperm with too many or too few chromosomes. As a result, fertilised eggs and the ensuing embryos may have trisomy (an extra chromosome of a particular pair) in each cell or monosomy (one chromosome fewer in each cell).
B. specific - meaning it is only able to catalyze a reaction with a certain molecule
upwelling cold sinks, warm rise. suponification
