In guinea pigs, dark hair (d) is dominant over light hair (d) and curly hair (c) is dominant over smooth hair (c). complete a dihybrid cross for parents with the genotypes: ddcc × ddcc and answer the following in complete sentences. 1. describe how you would set up a punnett square for this cross. 2. list the likelihood of each possible offspring genotype. 3. list the likelihood of each possible offspring phenotype.

First you need to see how the alleles can exist on their own. So FOR DdCc you can get: 
DC 
Dc 
dC 
dc 
the above alleles is what you do the cross with. In my diagram I will replace small c with u so that it doesn't get confusing, so you are crossing: 
DC 
Du 
dC 
du 

DDCC 1 = 6.25% Dark curly hair 
DDCu 2 = 12.5% Dark curly hair 
DdCC 2 = 12.5% Dark curly hair 
DdCu 4 = 25% Dark curly hair 
DDCu 1 = 6.25% Dark curly hair 

DDuu 2 = 12.5% Dark smooth hair 

ddCC 1 = 6.25% light curly hair 
ddCu 2 = 12.5% light curly hair 

dduu 1 = 6.25% light smooth hair 

The likelihood/probability of dark curly hair is 62.5% 
The probability of dark smooth hair is 12.5% 
The probability of light curly hair is 18.75% 
The probability of light smooth hair is 6.25