Find the correct statements:
A. In human pregnancy, the major organ systems are formed at the end of 12 weeks.
B. In human pregnancy the major organ systems are formed at the end of 8 weeks.
C. In human pregnancy heart is formed after one month of gestation.
D. In human pregnancy, limbs and digits develop by the end of second month.
E. In human pregnancy the appearance of hair usually observed in the fifth month.
Choose the correct answer from the options given below: 

The correct answer is A, C, D and E Only

Concept:

• Human pregnancy is a complex process divided into three trimesters, each contributing significantly to the development of the fetus. By the end of the embryonic phase (around 8 weeks), major organ systems begin to form.
• First month: In the first month, the heart begins to form and function.
  • The first sign of growing foetus may be noticed by listening to the heart sound carefully through the stethoscope.
• Second month: By the end of the second month, the foetus develops limbs and digits.
• Third month end: By the end of the third month, the major organ systems. For example, the limbs and external genital organs are well-developed.
• Fifth month: The first movements of the foetus and appearance of hair on the head are usually observed during the fifth month.
• Sixth month: By the end of the sixth month, the eyelids separate and the eyes begin to open and, the body is covered with fine 

Explanation:

• Statement A: "In human pregnancy, the major organ systems are formed at the end of 12 weeks" is correct. By 12 weeks, the major organ systems are developed.
• Statement B: "In human pregnancy the major organ systems are formed at the end of 8 weeks" is incorrect. During the embryonic phase (first 8 weeks), the major organ systems begin to form and not developed.
• Statement C: "In human pregnancy heart is formed after one month of gestation" is correct. The heart is one of the first organs to form, and its development starts early. By the end of the fourth week, the primitive heart tube begins to beat and pump blood, establishing early circulation.
• Statement D: "In human pregnancy, limbs and digits develop by the end of the second month" is correct. Limb buds appear during the fourth week, and by the end of the second month (8 weeks), digits begin to form as part of the embryonic development process.
• Statement E: "In human pregnancy the appearance of hair usually observed in the fifth month" is correct. Hair follicles start to develop by the fifth month of gestation, and fine hair called lanugo covers the fetus's skin to protect it.