Even methane (natural gas) is lighter than air, but not by much. Carbon dioxide, which is contained in the air we breathe out and is also easily and safely manufactured by mixing bicarbonate of soda and vinegar, is heavier than air. It tends to sink to the floor and accumulate. So it's a good job that houses aren't air tight.
Cuddling, holding, and sexual play releases chemicals, like oxytocin, in the brain that create a sense of well-being and happiness, says Dr. Renee Horowitz, an ob-gyn who recently opened the Center for Sexual Wellness in Farmington Hills, Michigan.
Ovulation - the maturing follicle prompts the release of higher amounts of oestrogen. The hypothalamus responds by secreting a chemical known as gonadotrophin-releasing hormone (GnRH), which makes the pituitary produce luteinising hormone (LH) and FSH. High levels of LH trigger ovulation within about two days.