Answer:
The prevalence of serious defects in this population at the time of birth is 10%.
Step-by-step explanation:
The prevalence of serious defects is the number of infants that were born with seriours birth defects divided by the total number of infants born.
In this problem, we have that:
There were 1000 newborn infants.
100 infants were born with serious birth defects.
Calculate the prevalence of serious defects in this population at the time of birth.
This is:

The prevalence of serious defects in this population at the time of birth is 10%.
Answer: 42.5
Step-by-step explanation:
The answer would be 7.99.
Test for symmetry about the x-axis: Replace y with (-y). Simplfy the equation. If the resulting equation is equivalent to the original equation then the graph is symmetrical about the x-axis. Example: Use the test for symmetry about the x-axis to determine if the graph of y - 5x2 = 4 is symmetric about the x-axis.
Test for symmetry about the y-axis: Replace x with (-x). Simplfy the equation. If the resulting equation is equivalent to the original equation then the graph is symmetrical about the y-axis. Example: Use the test for symmetry about the y-axis to determine if the graph of y - 5x2 = 4 is symmetric about the y-axis.
I didn't fully understand the question but this is the best I can do! Hope this helps! :D