Physical property is the characteristic that can be observed, using the five sense, without changing or trying to change the composition of the substance. Chemical property on the other hand is a characteristic of how the substance reacts. It can not be observed without changing the substance into something else. A physical change is a change in which the form or appearance of matter changes, but not its composition.
        
             
        
        
        
The correct answer is that "the T cell enters a state of anergy".
The activation of T cells requires two signals: (1) antigen specific signal presented by an antigen presenting cell (either a macrophage or a dendritic cell) that activates t cell receptors and (2) co-stimulatory signals that is not antigen specific but rather found in the plasma membrane of the antigen presenting cell (i.e. CD28). In the absence of a co-stimulatory signal, the t cell will enter a state of anergy or the inability to produce an immune response toward an offending antigen.
        
             
        
        
        
DNA (or deoxyribonucleic acid) is the molecule that carries the genetic information in all cellular forms of life and some viruses. It belongs to a class of molecules called the nucleic acids, which are polynucleotides - that is, long chains of nucleotides.
 
        
             
        
        
        
Answer:
it's 5 
Explanation:
today's atmosphere we enjoy today is radically different from the atmosphere that formed with the earth billions of years ago.