Cell membrane... i believe this to be the correct answer
        
             
        
        
        
Feathers are modified as scales. According to the history, birds which have feathers are the descendants of the dinosaurs which have scales.
That's why feathers are categorized as scales in the present record according to studies. <span />
        
             
        
        
        
Answer: All the statements of the question are correct.
Sickle cell disease is an autosomal recessive disorder that is characterized by formation of defective hemoglobin protein, which results in sickle shaped RBC ( red blood cell). 
This disease is caused by mutation in the gene that is responsible for the protein hemoglobin ( which transport oxygen throughout body). 
It is inherited by the offspring when both the mutated copy of genes ( one from each parent) are passed to him.
Carriers of the disease exhibit increased resistance to malarial parasites by controlling the level of free haem in the blood ( through enzyme heme oxygenase that produces a toxic carbon monoxide gas). The resistance thus developed, is a mutation.
Therefore, all the statements in the given question are correct.
 
        
             
        
        
        
Cancer or cell death could happen I got it right in my test