The amnion and chorion consist of which type of composition?

During embryogenesis,the zygote undergoes:

Where does the development of the zygote take place in viviparous organisms?

In humans,the foetal membrane which forms the intimate connection with the uterine tissue is:

After one month of pregnancy,the embryo's $A$ is formed. By the end of the $B$ month of pregnancy,the foetus develops limbs and digits. By the end of $C$,most of the major organ systems are formed,for example,the limbs and external genital organs are well-developed. By the end of $D$,the body is covered with fine hair,eyelids separate,and eyelashes are formed. Here $A$ and $D$ refer to:

Foetal sex can be determined by examining cells from the amniotic fluid by looking for