either of two large organs lying within the chest cavity on either side of the heart; they supply the blood with oxygen inhaled from the outside air and dispose of waste carbon dioxide in the exhaled air, as a part of the process known as respiration.
Most babies first pull themselves up to a standing position between about eight months and 10 months. At this stage your baby will need to hang on to you or a solid piece of furniture. By 11 months she may be able to stand on her own.
Your baby may be able to support herself in a standing position while holding on to something. If she can do this, she will still sit down with a bump (Sheridan 2014). Nine to 10 months: Your baby may be able to pull herself up to a standing position with the aid of a sturdy object, such as a sofa or table leg.