The _____ is the inner layer of the embryo from which the lungs ...

[LCritchfi]

The _____ is the inner layer of the embryo from which the lungs and digestive system develop.
 
  A) neural tube
  B) mesoderm
  C) endoderm
  D) umbilical cord

Question 2

Which of the following is a difference between primary sex characteristics and secondary sex characteristics?
 
  A) The primary sex characteristics are physical indicators of sexual maturation, while the secondary sex characteristics trigger the development of sex hormones.
  B) The primary sex characteristics are structures that make reproduction possible, while the secondary sex characteristics are not directly involved in reproduction.
  C) The primary sex characteristics include breast development, while the secondary sex characteristics include the ovaries and testes.
  D) The primary sex characteristics respond to pituitary hormones, while the secondary sex characteristics do not respond to pituitary hormones.

[enass]

Answer to Question 1

C

Answer to Question 2

B