The answer to this is B. Topaz
        
             
        
        
        
The reasons why  241am smoke detectors are perfectly safe is because;
(i)   The amount of americium is very little.
(ii)   The aluminium core is where the detector is hosted.
(iii)  The detector has a plastic cover.
(iv)   Radiation is limited in penetrating power.
(v)    There is a low number which is leaving the case.
(iv) ions get trapped by electrodes.
        
             
        
        
        
More nitrogen in the atmosphere leads to NITRIC ACID RAIN.
When nitrogenous fertilizers are used on the farm, some gases are released into the atmosphere including nitric oxide. These gases rises up into the atmosphere, mix with rainfall.
 Nitric oxide react with rainfall to form nitric acid and it falls as acidic rain.
        
                    
             
        
        
        
I think it is a sex cell (not sure)
        
                    
             
        
        
        
cAMP in the cytoplasm
Many cAMP can be generated as a second messenger to amplify the signal in response to hormone binding.