Answer:
It means the chemical entity is a radical
Explanation:
When we talk of unsaturation, we are referring to the number of pi-bonds in a chemical entity. The alkane, alkene and alkyne organic family are used to as common examples to explain the term unsaturation.
While alkynes have 3 bonds, it must be understood that they have 2 pi bonds only and as such their degree of saturation is two. 
In the case of an alkene, there is only one single pi bond and as such the degree of unsaturation is 1.
Now in this case, we have a fractional 0.5 degree of unsaturation alongside the 3 to make a total of 3.5. So what’s the issue here?
The fractional part shows that the chemical entity we are dealing with here is a radical. While the integer 3 shows that there are 3 pi-bonds, the half pi bond remaining tells us that there is a missing electron on one of the atoms involved in the chemical bonding and as such, the 1/2 extra degree of unsaturation tends to tell us this.
Kindly recall that a radical is a chemical entity within which we have at the least an unpaired electron. 
 
        
             
        
        
        
Answer: The answer is 185 Pm
 
        
                    
             
        
        
        
Answer: C) An electron has a high probability of being in certain regions.
Explanation: How does the electron-cloud model describe electrons? An electron has a high probability of being in certain regions.
***If you found my answer helpful, please give me the brainliest, please give a nice rating, and the thanks ( heart icon :) ***
 
        
             
        
        
        
Diffusion, facilitated diffusion, filtration, and osmosis