Earth has roughly surface times more atmospheric pressure than mars.
Sorry if it's wrong i tried!
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
During the first 2-3 weeks you will not see any physical signs. Look at your dog's nipples, for if it is pink, that may be an indication. Be sure to observe your dog's body and it's weight.

Cellular homeostasis involves maintaining a balance of several factors that make a cell healthy. The cell membrane is a lipid bilayer that prevents that passage of water and ions. This allows cells to maintain a higher concentration of sodium ions out the outside of the cell.