Carbon dioxide. Carbon dioxide (chemical formula CO2) is a colorless gas with a density about 60% higher than that of air (1.225 g/L) that is odorless at normally encountered concentrations. Carbon dioxide consists of a carbon atom covalently double bonded to two oxygen atoms.
You should only do ballet in pregnancy if you are used to it. Ballet stretches can place a lot of pressure on your joints, especially your pelvic joints, and standing on one leg can cause pain in your pelvis.
Yes, you can still get pregnant. I am still nursing my 15 month old and am 4.5 months pregnant with baby number two. I did not know when I was ovulating either so you just get to have some fun. But, what will prevent getting pregnant the most is the throughout the night nursing.