Milk is a nutritional source that provides the postnatal infant (= newborn, baby, and toddler, I just want to sound smart) with the first and most important nutrients he receives, as such it has a specific molecular makeup that was designed for a certain animal through evolution. (healthyeatingharbor.com)
Albumin and Edestin is a very similar molecular makeup as the protein found in the human body. (drjockers.com)
That way they could look at the planet's molecular makeup for signs of runaway greenhouse gases that could indicate an inhospitable Venus - like planet. (sciencedaily.com)