Answer:
The options to this question are:
A) allele 
B) codon 
C) nucleotide 
D) chromosome
The answer is A) allele
Explanation:
RNA and DNA are the two nucleic acids in living organisms used for transferring and storing genetic information. Deoxyribonucleic acid (DNA) is the genetic material in living organisms that contains segment coding for useful products/proteins and transmits genetic information from one generation to another. These segments are called GENES.
However, genes contain an alternate form responsible for genetic variation in the traits coded for by them. These alternate or variant form of a gene is called ALLELE. In a diploid organism like human, each trait is encoded by genes which contain contrasting pair of alleles that allows variation for that particular trait i.e. two alleles for each gene. For example, height trait in humans are encoded by gene, which possess two alleles; one coding for short variety (t) and the other for tall variety (T).
 
        
                    
             
        
        
        
Answer:
true 
Explanation: 
<em><u>Some water pollution is caused from “point sources” that is discrete locations, from which pollutants are discharged, e.g., a pipe, ditch, ship, or factory smokestack. Point sources originate in large and easy to trace facilities, hence are easier to control. In contrast, pollution from “nonpoint” sources is cumulative, arising from multiple inputs over larger areas, such as farms, city streets, and residential neighbourhoods. Hence, such sources are harder to precisely identify, and because of this uncertainty, nonpoint source pollution is harder to control than the point source.</u></em>
 
        
             
        
        
        
C. hemoglobin hope this helps
        
                    
             
        
        
        
Answer:
Gas exchange between tissues and the blood is an essential function of the circulatory. The air contains oxygen that crosses the lung tissue, enters the bloodstream, and the alveoli are in direct contact with capillaries of the circulatory system. As water flows over the gills, oxygen is transferred to blood via the veins.
Explanation: