During the second stage of labor, contractions usually occur: ...

[ss2343]

During the second stage of labor, contractions usually occur:
 
  a. every 5 to 6 minutes, with a duration of 30 seconds
  b. every 2 to 3 minutes, with a duration of 60 to 90 seconds
  c. every 2 to 4 minutes with a duration of 30 to 60 seconds
  d. every 1 minute with a duration of 120 seconds

Question 2

The purpose of the ovum's zona pellucida is to
 
  a. Make a pathway for more than one sperm to reach the ovum.
  b. Allow the 46 chromosomes from each gamete to merge.
  c. Prevent multiple sperm from fertilizing the ovum.
  d. Stimulate the ovum to begin mitotic cell division.

[Mochi]

Answer to Question 1

B
During the second stage of labor, contractions usually occur every 2 to 3 minutes, with a duration of 60 to 90 seconds.

Answer to Question 2

C
Feedback
A Once one sperm has entered the ovum, the zona pellucida changes to prevent
other sperm from entering.
B Each gamete (sperm and ovum) has only 23 chromosomes. There will be 46
chromosomes when they merge.
C Fertilization causes the zona pellucida to change its chemical composition so that
multiple sperm cannot fertilize the ovum.
D Mitotic cell division begins when the nuclei of the sperm and ovum unite.