Question

this passage describes the cystic fibrosis trait in humans:
cystic fibrosis is a condition that affects mucus. mucus is a jelly - like substance that certain cells produce to protect the body from infection. humans with cystic fibrosis produce mucus that is thicker and stickier than usual. this sticky mucus builds up in the lungs and interferes with breathing.
in a group of humans, some individuals have cystic fibrosis and others do not. in this group, the gene for the cystic fibrosis trait has two alleles. the allele ( f ) is for not having cystic fibrosis, and the allele ( f ) is for having cystic fibrosis.
nellie, a human from this group, does not have cystic fibrosis. nellie has one allele for not having cystic fibrosis and one allele for having cystic fibrosis.
based on this information, click the blue words to correct any errors in the text.
nellies phenotype for the cystic fibrosis gene is ( ff ).
nellie has cystic fibrosis. this is nellies genotype for the cystic fibrosis trait.
nellie is homozygous for the cystic fibrosis gene.

Explanation:

• Phenotype refers to the observable characteristics (like having or not having cystic fibrosis), while genotype is the genetic makeup (e.g., \(Ff\)). So “phenotype” should be changed to “genotype” in “Nellie's phenotype for the cystic fibrosis gene is \(Ff\)”.
• Nellie does not have cystic fibrosis as per the passage, so “has” should be changed to “does not have” in “Nellie has cystic fibrosis”. And since it's about the observable trait (not having the disease), “genotype” should be changed to “phenotype” in “This is Nellie's genotype for the cystic fibrosis trait”.
• Homozygous means having two identical alleles. Nellie has \(Ff\) (two different alleles), so “homozygous” should be changed to “heterozygous” in “Nellie is homozygous for the cystic fibrosis gene”.

Answer:

• Change “phenotype” to “genotype” in “Nellie's phenotype for the cystic fibrosis gene is \(Ff\)”.
• Change “has” to “does not have” and “genotype” to “phenotype” in “Nellie has cystic fibrosis. This is Nellie's genotype for the cystic fibrosis trait”.
• Change “homozygous” to “heterozygous” in “Nellie is homozygous for the cystic fibrosis gene”.