The correct answer is :
Some substances but not other can cross the (blank ) membrane of a cell. The   blank is to be filled with either cell or plasma. Cell membrane or plasma membrane is the living boundary of a cell which is made of phospholipid. It is a semi-permeable or differentially permeable membrane. It only allows small and non-polar molecules to pass through it. It prevents polar ions or molecules to pass through it   
 
        
             
        
        
        
Most scientific questions are based off of theory.
        
             
        
        
        
The guinea pig and the raccoon are both members of :
The eukarya domain, the kingdom of animals, the chordates and the mammal class.
After the level of class (Mammalia), they start to belong to different groups.
The guinea pig belongs to rodents and the raccoon belongs to the carnivores.