During the second month, the embryo goes through rapid development. The heart is functioning. All major organs and body systems begin to develop, including the brain, lungs, liver and stomach. Eyelids form but remain sealed shut. The inner ear begins formation, as do the face and features. The first bone cells appear. Ankles, wrists, fingers, toes and sexual organs are developing. The placenta is functioning and the umbilical cord is present. The baby looks more like a person than a tadpole and will measure slightly more than an inch and weigh less than 1ounce at the end of this month.