Question

carp are large freshwater fish that are often raised for food. before a carp is cooked, its scales are usually removed. normally, carp are covered in small scales arranged in straight rows. but carp with mirror scales have large scales arranged in scattered patches. because mirror scales do not cover the fishs entire body, carp with mirror scales are easier to prepare for cooking.

in a group of common carp, some individuals have normal scales and others have mirror scales. in this group, the gene for the scale type trait has two alleles. the allele a is for normal scales, and the allele a is for mirror scales.

a certain common carp from this group has mirror scales. this carp has two alleles for mirror scales.

based on this information, click the blue words to correct any errors in the text.

this common carp is heterozygous for the scale type gene.

this common carps phenotype for the scale type trait is normal scales.

this common carps genotype for the scale type gene is aa.

Explanation:

1. For the first sentence: A heterozygous genotype has two different alleles (e.g., Aa), but the carp has two alleles for mirror scales (aa), so it's homozygous recessive. So "heterozygous" should be changed to "homozygous".
2. For the second sentence: The carp has mirror scales, so its phenotype (physical trait) is mirror scales, not normal scales. So "normal scales" should be changed to "mirror scales".
3. For the third sentence: The carp has two alleles for mirror scales (a is the allele for mirror scales), so its genotype is aa, which is correct. So no change here.

Answer:

1. Change "heterozygous" to "homozygous" in "This common carp is heterozygous for the scale type gene."
2. Change "normal scales" to "mirror scales" in "This common carp's phenotype for the scale type trait is normal scales."
3. The sentence "This common carp's genotype for the scale type gene is aa." is correct, no change.