So they can say the number quicker. 
        
                    
             
        
        
        
Answer;
A) island forms and mainland forms descended from common ancestors.
Explanation;
-Islands tend to host very distinct but limited sets or species; on a given island a spectacular collection of one related group of species would be present and thriving, but many entire families or even higher taxa would be completely absent.
-All the species on the islands and the nearest continent are closely related to one another, however, each species had a set of adaptations that suits it for a particular environment. This means that the island forms and mainland forms descended from common ancestors.
 
        
             
        
        
        
Photosynthetic organisms, also known as photoautotrophs, are organisms that are capable of photosynthesis. Some of these organisms include higher plants, some protists (algae and euglena), and bacteria
c) autotrophs only