Beginning at about age 11, boys develop relatively more ...

[jwb375]

Beginning at about age 11, boys develop relatively more _______________.
 
  Fill in the blank(s) with correct word

Question 2

Describe the function and purpose of the placenta and explain what types of harmful substances can break through the placental barrier and possibly harm the fetus.
 
  What will be an ideal response?

[dominiqueenicolee]

Answer to Question 1

muscle

Answer to Question 2

Mother and embryo have separate circulatory systems. The pancake-shaped placenta contains a membrane that acts as a filter that permits oxygen and nutrients to reach the embryo from the mother, and permits carbon dioxide and waste products to pass to the mother from the embryo. The mother then eliminates them through her lungs and kidneys. Germs that cause syphilis and German measles and drugs like aspirin, narcotics, alcohol and tranquilizers, can cross the placenta and affect the fetus.

[jwb375]

TYSM

[helenmarkerine]

Thanks for the timely response, appreciate it