Answer:
Changes in gene expression
Explanation:
 
        
                    
             
        
        
        
Answer:
X. Mechanisms and habits that include limit water loss.
Explanation:
Many mammals that live in dry ecosystems tend to have above adaptations because there is a shortage of water in these areas. And of course water is the most essential thing for survival.
 
        
             
        
        
        
Allan already had a heart attack and can try to prevent another one by changing the diet, exercising, or even quit smoking, but there are non-modifiable risks such as age, sex and generic heritage, so If Allan is over 40 years old, male or comes from a family with heart diseases,  Allan needs to be extra careful because those factors cannot be changed no matter how the way of life is changed.
        
             
        
        
        
It is a vestigial Structure.
Explanation: