Question

a student is doing a genetics experiment on beetles. a pure green beetle is crossed with a pure brown beetle. the student repeats this experiment ten more times. every time he performs this cross, all of the offspring are green. what can the student conclude? a the gene for green color is dominant over the gene for brown because all the beetle offspring have a brown phenotype. b the gene for green color is dominant over the gene for brown color because all the beetle offspring have a green phenotype. c the gene for brown color is dominant over the gene for green color because all of the beetle offspring have a brown genotype. d the genes for green and brown color are equally expressed because half the beetle parents have a green phenotype and half the beetle parents have a brown phenotype

Explanation:

In genetics, when a pure - bred (homozygous) green beetle is crossed with a pure - bred (homozygous) brown beetle, and all the offspring show the green phenotype. According to Mendelian genetics, if a trait is expressed in the offspring when two pure - bred parents with different traits are crossed, the trait that is expressed is the dominant trait. Here, the green color is expressed in all offspring, so the gene for green color is dominant over the gene for brown color.

Answer:

B. The gene for green color is dominant over the gene for brown color because all of the beetle offspring have a green phenotype.