White blood cells ( lymphocytes is correct though)
 
        
                    
             
        
        
        
They are warned about contracting Toxoplasma.
        
             
        
        
        
Answer: There are few ‘laws’ in science. Those ‘laws’ are so named for historical reasons, but they are theoretical in nature. They set out what happens when a theory is applied in practice. A theory is simply the best explanation we have for understanding why some process takes place and predicting what the result will be. 
Explanation: Anyone who describes something as “just a theory” does not understand what a theory is. Laws are arbitrary human rules. Theories are severely tested and re-tested explanations of why things happen in the real physical world and can be used to make predictions about outcomes.
Some would say that theories are about why something happens and laws (in science) describe what happens. But this simply makes a scientific ‘law’ a subset of a scientific theory, explaining how to make predictions.
 
        
             
        
        
        
The selective pairing of adenine (A) with thymine (T) and guanine (G) with cytosine (C) is based on the number of hydrogen bonds established between one of the purine bases and the one pyrimidine bases
        
             
        
        
        
Substances that are made up of only one type of atom.