Answer:
Sexual selection
Explanation:
It is sexual selection because it is a type of natural selection in which an organism or organisms acquire traits which help the individual to be choose as a mating partner or to have preference for a mating partner or for competition among one sex organisms in which a traits succeed.
Sexual selection can be intrasexual or or intersexual. Intrasexual is is competition between one sex of the same organism and intersexual is between sexes of different organism.
 
        
             
        
        
        
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.
 
        
             
        
        
        
The answer is horizontal gene transfer. 
Horizontal gene transfer enables gene flow between genomes of two organisms. It is a common process between different species of <span>prokaryotes and even, between  prokaryotes and eukaryotes. </span>When trying to reconstruct evolution and phylogenetic relationship, scientists face some difficulties because they cannot say the common gene transfer with the horizontal one.
        
             
        
        
        
The correct answer is option D The population of foxes would probably decrease. 
A food chain can be defined as a linear sequence of organisms through which the nutrients and energy flow as one organisms feeds on the other. Each level of the food chain is called the trophic level. They show organisms starting from the producers and end with consumers or sometimes with detrivores or decomposers. The producers which use solar energy and prepare their food occupy the first trophic level, followed by the primary, secondary, tertiary, quaternary consumers occupying the next trophic level.
In the terrestrial food chain given above, grass → rabbit → fox, the decrease in the any population will effect the other organism at a different trophic level of the food chain. A sudden decrease in the population of rabbits will decrease the population of the foxes at the next trophic level as it is a secondary consumer feeding on the primary consumer which is the rabbit. So, a sudden decrease in the rabbit population will starve the foxes and thus decrease their number in the island. 
 
        
                    
             
        
        
        
The answer is called photosynthesis. Hope this helps.