Leukocytes are not limited to blood. They occur elsewhere in the body as well, most notably in the spleen, liver, and lymph glands. Most are produced in our bone marrow from the same kind of stem cells that produce red blood cells. Others are produced in the thymus gland, which is at the base of the neck.
Once your baby is past 3 months than that is no longer a newborn. But that isn't considered a toddler either yet. They are a baby up until they start to walk then they are called a toddler. Source(s): My opinion. chicken2008 Â· 6 years ago. Thumbs up. 0. Thumbs down. 0. Comment.
Merriam-Webster dictionary simply says a newborn is a baby who is recently born and does not put an upper limit to the term. The dictionary also defines an infant as a child in the first stage of life but doesn't give any age specifics. The World Health Organization (WHO) defines a newborn, or neonate, as a baby under 28 days old. As the name implies, a toddler is classically defined as a child who is just learning to walk or one who toddles. This is often around one year of age. There's no official definition of the upper limit of toddlerhood.