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.

Let's analyze each of the statements regarding embryonic development during human pregnancy step-by-step:

Statement A: "In human pregnancy, the major organ systems are formed at the end of 12 weeks."
This statement is correct. By the end of the first trimester (12 weeks of pregnancy), most of the major organ systems are formed. For instance, the limbs and external genital organs are well-developed.

Statement B: "In human pregnancy the major organ systems are formed at the end of 8 weeks."
This statement is incorrect. While limbs and digits are formed by the end of 8 weeks (the second month), the formation of major organ systems is not completed until the end of 12 weeks (the first trimester).

Statement C: "In human pregnancy heart is formed after one month of gestation."
This statement is correct. The heart is the first organ to form in the growing embryo, and its formation is completed after one month of gestation.

Statement D: "In human pregnancy, limbs and digits develop by the end of second month."
This statement is correct. By the end of the second month of pregnancy (around 8 weeks), the fetus develops distinct limbs and digits.

Statement E: "In human pregnancy the appearance of hair usually observed in the fifth month."
This statement is correct. The first movements of the fetus and the appearance of hair on the head are typically observed during the fifth month of gestation.

Therefore, statements A, C, D, and E are correct, making "A, C, D and E Only" the correct option.