Answer:
2. Hip bones
Explanation:
More than 40 million years ago, whales had ancestors who walked on land. Even now, they have a feature they inherited from them - hip bones. Scientists used to think that they are vestigial, i.e. that they lost their function. However, recently they discovered that these bones help whales (and other marine mammals who have them, such as dolphins) maneuver better mating.
Whales developed the rest of the listed features later, when they became marine animals. This is why they are incorrect.
 
        
             
        
        
        
Answer:
This composition of nucleotide given in the question do not obey the chargaff"s rule.
Explanation:
According to chargaff"s rule the total number of purine bases will be same to the total number of pyrimidine bases that is 
           Adenine+Guanine=Thymine+Cytosine 
But here the above quation is not maintained because according to the question A+G=49%
         and T+C = 51%.
Such DNA is replicated by rolling circle model.
 
 
        
             
        
        
        
RNA is an abbreviated form for Ribonucleic Acid. RNA is a nucleic acid that is present in the cells of all living things. Its primary function is to carry genetic instructions from DNA to ribosomes for the synthesis of proteins. There are three different types of RNA, these are messenger RNA, ribosomal RNA and transfer RNA. Ribosomal RNA are transcribed in the nucleus and the are the RNA components of the ribosomes. 
        
                    
             
        
        
        
D. Cross braces this is the right answer