Liquid.
Earth can sustain life because it contains liquid water.
        
                    
             
        
        
        
Answer:
<em>The correct options are:</em>
<em>Prior to process 1, DNA should copy itself to allow the cell to divide.</em>
<em>Between processes 1 and 2, the mRNA must be modified before leaving the  nucleus.</em>
Explanation:
For eukaryotes, the mRNA is made in the nucleus from the DNA. This process in known as transcription. The process of making proteins from the mRNA takes place in the ribososmes of the cytoplasm. This process is known as translation. The mRNA has to be modified before it is transported for translation. Otherwise, the mRNA will be degraded by the enzymes of the nucleus. 
 
        
                    
             
        
        
        
Answer:
After the water soluble hormone approaches its target, the last thing that happens in change in cell activity and the hormones send a signal/message to the original hormone.
Explanation:
Water soluble hormones easily attach themselves to the cell. These water soluble hormones are made up of amino acid. Amino acid are basically proteins which are easily soluble in water. 
These water soluble hormones cannot enter the cell membrane of the cell because they are made up of fat cells. 
 
        
             
        
        
        
The best answer is  B - Proteins.
Proteins make up enzymes, or to put it another way enzymes are made up of protein. It is enzymes that speed up the chemical reactions. Enzymes are organic catalysts, substances that speed up a (biochemical) reaction but do not take part in the reaction and remain unchanged at the end of the reaction.
In man, there are many enzymes. The majority of these are found in the digestive system where they greatly aid the process of food breakdown from complex molecules to simple molecules. Examples include salivary amylase found in saliva,  which begins the gradual breaking down of starch into glucose right from the moment food is placed in the mouth and mixed with saliva. Pepsin in the stomach breaks down protein.
 
        
             
        
        
        
C no because many species went extinct without leaving fossils behind