I think it is because the cold air is more dense than the hot air so the less dense air which is the warm air rises
        
             
        
        
        
Sickle cell anemia<span> is the result of a point mutation, a change in just one nucleotide in the gene for hemoglobin. This mutation </span>causes<span> the hemoglobin in red blood cells to distort to a sickle shape when deoxygenated.</span>
        
             
        
        
        
Fermentation doesn't need oxygen in its process while respiration needs oxygen.
Fermentation is also known as anaerobic respiration and respiration is known as aerobic respiration.
        
             
        
        
        
Answer:
A
Explanation:
<em>The field of </em><em>recombinant DNA technology</em><em> is a thoroughly modern discipline that has led to new ways to treat infectious diseases.</em>
<u>Recombinant DNA technology involves the process of combining DNA of different organisms and inserting such in a host organism in order to elicit desirable genetic characters that could be of value to different fields in science.</u> 
The fields in which recombinant DNA technology has found applications include agriculture, medicine, and industrial productions. With this technology, new drugs and methods of treating diseases have been developed in the area of medicine, disease-resistant crop varieties have been developed in agriculture, and important chemicals for production have been developed in industries.
<em>Correct option:</em><em> A</em>