Imagine that long fins in zebrafish is a dominant trait. a breeder wants to set up a breeding program beginning with homozygous dominant long-finned fish. if she obtains a handful of the long-finned fish, how can she tell which if any of these are homozygous for the trait? a. cross the long-finned fish with short-finned fish; if three-fourths of the offspring are long-finned and one-fourth are short-finned, the long-finned parent is homozygous. b. cross the long-finned fish with short-finned fish; if half the offspring are long-finned and half are short-finned, the long-finned parent is homozygous. c. cross the long-finned fish with short-finned fish; if four-fifths of the offspring are long-finned and one-fifth are short-finned, the long-finned parent is homozygous. d. cross the long-finned fish with short-finned fish; if the offspring are all long-finned, the long-finned parent is homozygous.

D - Cross the long-finned fish with short-finned fish; if the offspring are all long-finned, the long-finned parent is homozygous.

Explanation:

Since long fins is a dominant trait, a cross between homozygous dominant long-finned fish and short-finned fish should results in all long-finned offspring.

If long fin allele is L, homozygous long fin will be LL and short fin will be ll

                  LL    x    ll

This will result in Ll, Ll, Ll, Ll genotype offspring and since L is dominant, all the offspring will have long fin.

Hence, in order to for the breeder to tell which of the long-finned fish is/are homozygous for the trait, all she needs to do is mate each of the long-finned fishes with a short-finned fish. Anyone that yields all long-finned offspring is homozygous for the trait.

The correct option is D.

the solute can move "downhill," from regions of higher to lower concentration, relying on the specificity of the protein carrier to pass through the membrane. this process is called passive transport or facilitated diffusion, and does not require energy.

my teacher would say no s