50.The first sign of the growing foetus may be noticed by listening to the heart sound carefully through the stethoscope. Embryo’s heart is formed ___. A. By the end of the second month of pregnancy B. By the end of first trimester C. After one month of pregnancy D. During fifth month
option B . Growing human develops coronary heart at a completely early level across the 5th week of the gestation duration and it began out operating so it's far very not unusualplace that heartbeat is detected and it's far taken into consideration because the boom sign. So the ideal alternative is 'Listening coronary heart sound'.
