The allele HC results in the phenotype of curly hair while the allele HS results in straight hair. Individuals with the genotype HCHC have curly hair, those with HSHS have straight hair, and those with HCHS have an intermediate phenotype of wavy hair that is neither straight nor curly. What type of genetic phenomenon is observed in this example?

The correct answer is incomplete dominance.

Explanation:

The phenomenon that takes place when neither of the two alleles is completely recessive or completely dominant towards each other is termed as incomplete dominance. In the phenomenon, the expression of both the alleles takes place, and the physical trait or the phenotype shows the blend of the two alleles present.  

In incomplete dominance, it is clear that neither of the alleles shows dominant characteristics, and in the case when the offspring is heterozygous, that is, comprising alleles of both the traits then the phenotype shown by the offspring would be the mixture of both the alleles present in the parents. Hence, the given case is an illustration of incomplete dominance.  

clumped distribution, because you'de have all of the population gathered in a relatively small are.

it's the most common because it provides protection and a mate for reproduction

example: humans, seeweed, cattles, etc.