Answer and Explanation: The excretory system helps the respiratory system by getting rid of carbon dioxide. The respiratory system helps the excretory system by getting rid of CO2 from the body. They both need each other and if one or the other did not exist, we might've not been able to survive. Tis demonstrates how vital they are for the human body. 
 
        
             
        
        
        
Answer:
each mile is an hour
Explanation:
 each mile is an hour depending on how fast your going like when ur in bed with another person. feels good and fast at the same time to reach the destination 
 
        
             
        
        
        
Answer:
b. Forward or reverse primers
Explanation:
Sanger sequencing is a technique of DNA sequencing based on the extension of DNA fragments with variable sizes terminated with dideoxynucleotides at the 3′ end. This technique was developed by Frederick Sanger in 1977. In Sanger sequencing, a short primer is added in order to bind by complementarity to the target DNA region of interest. Subsequently, a DNA polymerase adds nucleotides (A, T, C and G) in the 5'-3' direction. Finally, the extension of the DNA strand is stopped by adding dideoxynucleotides, which are nucleotide analogs (i.e., modified nucleotides) that act as DNA synthesis terminators.
 
        
             
        
        
        
Answer:
Artifical Selection OR Cross Pollination 
Explanation:
If white roses and red roses are cross-bred by scientists, it would be artifical selection. If they were crossed in nature, it is called crossed pollination.
 
        
                    
             
        
        
        
Answer:
B. 0.42
Explanation:
Since the two alleles are at Hardy-Weinberg equilibrium, the sum of the frequency of two alleles will be one. If the frequency of a dominant allele is "p" and that of the recessive allele is "q", then p+q=1
According to the given information, the frequency of one allele in the population is= 0.7
This means that the frequency of the other allele would be= 1-0.7 = 0.3
Frequency of heterozygote in the population =2pq = 2 x 0.7 x 0.3 = 0.42