Answer:

The exposure may be risk factor.
Explanation:
Given

Required
The odd ratio
First, we calculate the odds of exposure using:

For cases, we have:


For controls, we have:


So, the odds' ratio is:



Conclusion about the odds' ratio
The calculated ratio is greater than (and also far from) 1.
This implies that there is a greater exposure than the controls.
So, we can conclude that the exposure may be risk factor.
Answer:
I think the answer is first option
Explanation:
a. excessive bleeding
A periodontist specializes in the tissue surrounding and supporting the gum.
the medical definition of periodontal means “investing or surrounding the tooth”, which is exactly what the gum does.
hope this helps!