It is called a contusion. Hope this helps.
        
             
        
        
        
Answer:
Planet B is expected to be cooler than Planet A.
Explanation:
In the given case, planet A is closer to the star than planet B. Their atmospheric conditions and mass is same so their surface temperature will depend on their distance from the star. Since planet A is closer, it will receive more radiation from the star. In turn it will be hotter to re-radiate that energy back to space. Hence, average surface temperature of planet B will be lower than planet A. 
 
        
             
        
        
        
Answer:
The correct answer would be - d. With the end of genetic isolation gene flow took place
Explanation:
It is given that people of Troublesome Creek Kentucky were isolated and have a rare recessive allele that results in a blue tone to their skin. However, later these isolated people connected with the people from outside, and due which allow them to intermate. Intermating among populations from isolated and people from outside leads to gene flow.
Methemoglobinemia was present in the isolated population as they had both recessive alleles in their genotype and other hand people from outside might have heterozygous or both dominant allele genotypes that make them free from this disorder. 
Due to the intermating and gene flow, the number of heterozygous conditions rises and after many generations slowly methemoglobinemia could have disappeared due to the masked recessive allele.
 
        
             
        
        
        
Genetic variation or coral spawning
        
                    
             
        
        
        
Answer:
The purine ring is built onto ribose-5-phosphate of PRPP for its de-novo nucleotide biosynthesis, while the ring structure of the pyrimidine bases are synthesized separately and then coupled to ribose-5-phosphate via the C-N glycosidic bond.
Explanation:
In the de novo synthesis of nucleotides, their metabolic precursors such as aminoacids, ribose-5-phosphate, CO₂ and NH₃ are used as starting materials.
In purine  nucleotide synthesis, the ring structure is built up on ribose-5-phosphate of PRPP by addition of one or a few atoms one at a time starting with the amino group donated by glutamine until the first intermediate inosinate is synthesized.
In pyrimidine ring synthesis, orotate is first synthesized from carbamoyl phosphate and aspartate, and then is attached to ribose-5-phosphate of PRPP, before it is then converted to the common pyrimidine nucleotides starting from uridylate.