In mice, brown eyes (b) are dominant over blue (b). a homozygous brown-eyed male mouse mates with a blue-eyed female and they have offspring. what are the phenotypes and genotypes of their offspring? what are the genotypes of the parents?

Parents: Homozygous brown-eyed (M) - B B
                                    blued-eye (F)     -  b b    [since blue (b) is recessive then                                                                                      and brown (B) is dominant then
                                                                           in order for the blue gene to
                                                                           show the you need double                                                                                              recessive or the brown
                                                                           gene absent 

Offspring:
So based on the Punnett cross then you realize that all the possible of spring carry the genotype B b and as such the phenotype brown eyes
                                                                          

Twins are born minutes apart, not a year apart. fraternal twins are no more closely related genetically than ordinary siblings born a year apart. they just happen to be born at the same time. identical twins result from a single fertilized egg dividing and separating early in gestation. although identical twins are more similar to each other than other siblings, there is some research to suggest they are not 100% the same. you and your brother share very similar dna because you have the same parents, and you look the same. i'll bet you resemble one or both of your parents, and likely a grandparent or two as well.