Answer:
Because older cultures of gram-positive bacteria tend to lose their ability to retain crystal-violet in the peptidoglycan of their cell walls and can be confused with gram-negative bacteria.
Explanation:
Gram staining is used to differentiate between two major groups of bacteria. Gram-positive and gram-negative, these bacteria differ in the amount of peptidoglycan in their cell walls. Gram-positive bacteria have a higher amount of peptidoglycan, which absorbs the violet crystal complex used in gram staining, staining them purple/violet. Old cultures of gram-positive bacteria tend to lose the ability to retain the violet crystal and are stained by safranine, staining them red/pink and appear to be gram-negative.
 
        
             
        
        
        
It is The shoot and the root systems 
        
                    
             
        
        
        
Fossil Fuels; Once they run out ,humans can not replacing them.
        
             
        
        
        
Answer:
not significant to the overall mass of the atom
Explanation:
The mass number of an atom is the combination of the mass of the protons and neutrons.  Electrons are not included because their mass are so insignificant that is doesn't change the total mass much, therefore they are left out. The mass of an electron is about 1,830 times smaller than protons and neutrons.
 
        
             
        
        
        
Answer:
Unfortunately, you can rarely identify a mineral only by its color. Sometimes, different minerals are the same color. For example, you might find a mineral that is a gold color, and so think it is gold. But it might actually be pyrite, or “fool's gold,” which is made of iron and sulfide.
Explanation: