Answer: Option B) each parental strand serves as a template for the synthesis of a complementary strand 
Explanation:
In semi-conservative DNA replication,
- a parent double-stranded DNA splits in two.
- Each strand is then read by the enzyme, DNA polymerase, to ensure accurate replication of a newly synthesized strand
- the new strand contains nucleotides that are complimentary to free nucleotides present in the parent strand.
Thus, option B perfectly describes semi-conservative replication of dna
 
        
             
        
        
        
Answer:
Helicase
Explanation:
DNA replication is the process in which DNA makes copies of itself.
The process of DNA  replication is supported by several enzymes. 
The initial step of DNA replication is unwinding of double stranded DNA which is catalyzed by helicase enzyme. Helicase enzymes breaks the hydrogen bond between the  DNA strands and prepare them for replication process.
Hence, the correct asnwer is "Helicase".
 
        
             
        
        
        
Answer:
a) the son will not be affected by rickets (0% chance)
b) the daughter will have rickets (100% chance)
Explanation:
Since only the father has rickets and it is a X-linked dominant trait, the mother has two normal X chromosomes. The X chromosome received from the mother by the son will not result in the rickets since the father will have contributed the Y chromosome and that does not have the gene for rickets. In case of the daughter, she will receive the defective X chromosome from her father, which will cause her to have the rickets disease.
Hope that answers the question, have a great day!