In mammoths, assume that spotted skin (S) is dominant over non-spotted skin (s) and that wooly hair (W) is dominant over non-wooly hair (w). Cross a mating between a heterozygous spotted, non-wooly mammoth with a heterozygous wooly-haired, non-spotted mammoth. Give genotypic and phenotypic ratios of offspring.

Genotypic and Phenotypic ratios → 1:1:1:1

Explanation:

Available data:

Parentals) Ssww   x   ssWw

Gametes) Sw, Sw, sw, sw

                 sW, sW, sw, sw

Punnett square)     Sw            Sw           sw           sw

                  sW      SsWw      SsWw      ssWw     ssWw

                  sW      SsWw      SsWw      ssWw     ssWw

                  sw      Ssww       Ssww       ssww      ssww

                  sw      Ssww       Ssww       ssww      ssww

F1) 4/16 = 1/4 = 25% of the progeny is expected to be SsWw, exhibiting spotted skin and wooly hair

    4/16 = 1/4 = 25% of the progeny is expected to be Ssww, exhibiting spotted skin and non-wooly hair

    4/16 = 1/4 = 25% of the progeny is expected to be ssWw, exhibiting non- spotted skin and wooly hair

    4/16 = 1/4 = 25% of the progeny is expected to be ssww, exhibiting non-spotted skin and non-wooly hair.

Genotypic and Phenotypic ratios → 1:1:1:1

answer: the blood-brain barrier is a layer of specialized membranes and cell processes designed to keep undesirable substances from passing from the bloodstream into the precious tissues of the brain. while the blood-brain barrier does keep most bad things out of the central nervous system, it is not impermeable.

explanation:

the answer to your question is:

c. complementary base-pairing