Two rats are mated. Both are heterozygous brown fur, heterozygous straight tail heterozygous long whisker. Tan, kinked tail, and short whiskers are...

All the crosses within your question involve two heterozygous phenotypes. A heterozygous genotype consists of one dominant and one recessive allele. Assuming that all of the crosses mentioned within your question are monohybrid crosses, each will result in the same phenotype and genotype ratios for the offspring produced. If we allowed a “H” to represent the dominant allele within a generic heterozygous genotype and a “h” to represent the recessive allele, then the following Punnett square would result for any cross involving two heterozygous genotypes :

           H                             h

H         HH                         Hh

h        Hh                         hh

Therefore, all crosses involving two heterozygous crosses will always result in the following genotype ratio:

Homozygous dominant = 25%

Heterozygous = 50%

Homozygous recessive = 25%

Likewise, all crosses involving two heterozygous crosses will always result in the following phenotype ratio:

Dominant = 75%

Recessive = 25%

Thus, if brown (B) is dominant to tan (b), the following genotype ratios would result:

BB = 25%

Bb = 50%

bb – 25%

The corresponding phenotype rations would be:

Brown = 75%

Tan = 25%

Likewise, if straight tail (S) is dominant to kinked tail (k), then the following genotype ratios would result:

SS = 25%

Ss = 50%

ss – 25%

The corresponding phenotype rations would be:

Straight tail = 75%

Kinked tail  = 25%

Finally, if long whiskers (L) are dominant to short whiskers (l), then the following genotype ratios would result:

LL = 25%

Ll = 50%

ll – 25%

The corresponding phenotype rations would be:

Long tail = 75%

Short tail = 25%