3.4 Essay Questions 1) Explain how conjoined twins may occur. 2) Briefly describe the two cellular layers that comprise the bilaminar embryonic disc and explain their importance in embryonic...

3.4 Essay Questions

1) Explain how conjoined twins may occur.

2) Briefly describe the two cellular layers that comprise the bilaminar embryonic disc and explain their importance in embryonic development.

3) Describe the types of tissues that make up the endoderm, ectoderm, and mesoderm, and explain how these tissues relate to their developmental processes.

4) Define the term
teratogen, and explain why exposure to teratogens during the first 8 weeks of pregnancy is particularly dangerous.

5) Briefly describe the formation of the nervous system.