In human beings, at the end of 12 weeks (first trimester) of pregnancy, the following is observed:

Step-by-step solution

1. In human beings, after one month of pregnancy, the embryo’s heart is formed. The first sign of a growing foetus may be noticed by listening to the heart sound carefully through the stethoscope, placed on the abdomen of the mother. 2. By the end of the second month of pregnancy, the foetus develops limbs and digits. 3. By the end of 12 weeks first trimester , most of the major organ systems are formed, and the limbs and external genital organs are well-developed. 4. The first movement of the foetus and the