A human with heterozygous genotype can have a dominant phenotype if one of the alleles complete mask the effects of the other.
- Heterozygous genotype involves two different alleles, unlike homzygous genotypes in which the alleles are the same.
- When the two alleles of an heterozygous genotype exert equal effects on one another, they are said to be codominant.
- When one of the alleles of an heterozygous genotype incompletely exert its effects on the other allele, it is said to be incomplete dominance.
- When one of the alleles complete dominates and masks the effects of the other allele, it is said to be dominant.
Hence, a dominant allele will always produce a dominant phenotype even if the genotype of the organism is heterozygous.
More on genotypes can be found here: brainly.com/question/14398652
 
        
             
        
        
        
The three substances that cause a double displacement reaction to occur are:
(i)   Ionized compounds. These are usually water.
(ii)   A gas that bubbles out a solution.
(iii)  A precipitate.
In double displacement reaction is where two new compounds are formed when two parts of two compounds switch places. For example; when sodium chloride combines with silver nitrate, the two new compounds formed are Sodium nitrate and silver chloride reason being sodium and silver switched places.
        
             
        
        
        
True as it saves natural resources and from pollution of land.
 
        
             
        
        
        
The kidneys filter any unwanted wastes from the body.<span> The glomerular filtration, reabsorption, and secretion take out any wanted fluids from your body when you drink water.</span> 
        
             
        
        
        
I think its A (hope i helped)