7.    a) P₁ = BBtt x bbTT            F₁ = 4 BbTt : 0,    all black whiskers with long tails

       b) BbTt x BbTt
   F₂ genotype ratio =   1 bbTT : 2 BbTt : 1 BBtt
   F₂ phenotype ratio =    1/4 white whiskers with long tails
                                     1/2 black whiskers with long tails
                                     1/4 black whiskers with short tails

8.    a) The offspring has a third phenotype which is different from either parent, i.e., the heterozygote does not have the same phenotype as either parent.  The two alleles for ear height show incomplete dominance (use E^S for the short-ear allele, and E^L for the long-ear allele).
       b) short-eared (E^SE^S) x  long-eared (E^LE^L), medium-eared (E^SE^L)

9.    a) both E^SE^L
       b) 1 short-eared (E^SE^S) : 2 medium-eared (E^SE^L) : 1 long-eared (E^LE^L)

10.  a) male (X^fY) x female (X^FX^F or X^FX^f)
       b) X^fY x X^FX^F
                1 X^FX^f : 1X^FY, all curly
           or X^fY x X^FX^f
                1 X^FX^f : 1 X^FY : 1 X^fX^f : 1 X^fY;
                  1 female, curly : 1 male, curly : 1 female, straight : 1 male, straight

       c) male (X^fY) x female (X^FX^f), offspring (X^fY)
           The male offspring received his X^f from his mother, and his Y from his father.
 

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