The stem is the part of the plant which contains vascular tissue. or the piping, of the plant
        
             
        
        
        
It consist of integral proteins and trans-membrane proteins and peripheral proteins as well 
        
             
        
        
        
Answer:

Explanation:
An element only has <u>one</u> type of atom and cannot be broken down by chemical means. 
Let's analyze the answer choices. 
1. This has two types of atoms, so it cannot be an element. It has more than one type of atom. 
2. This has two types of atoms that are bonded together. It cannot be an element because there is more than one type of atom and the bonds can be broken. 
3. This has one type of atoms, so it is an element.  
Therefore the best answer choice is 3.
 
        
             
        
        
        
Answer:
The antibodies produced by a vaccine only fight specific antigens.
Explanation:
Antibodies only bind to specific antigen during an immune reaction. The introduction of foreign substance in the body stimulate the B-cells to produce antibodies that fight against infections. Only specific antibodies are produced following antigen presenting cells that bind to antigens. They capture and display the antigens to the antibodies. 
 
        
                    
             
        
        
        
A. To remove excess Heat from the body