Answer:
You have external defense systems, which include your skin, tears, mucus, saliva, stomach acid, cilia (small hairs) and helpful bacteria. The skin, nails and hair form the integumentary system, which stops dirt and pathogens from entering the body.
Answer:
Life Processing I Learnes this last year in 7 grades
Answer:
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Answer:
The correct answer is 4: "The exception to Mendelian laws of inheritance that best explains the mentioned symptoms is codominance".
Explanation:
In codominance, both alleles can be expressed. In these cases, heterozygote individuals<em> instead</em> of showing an <em>intermediate phenotype</em>, express both of the alleles. Their phenotype is an additive expression of their parents' genes.
In cystic fibrosis, there is a gene responsible for coding for a protein named "cystic fibrosis transmembrane conductance regulator, CFTR".
-Most of the people have two copies of the normal allele and produce the functional CFTR protein form.
-Patients with cystic fibrosis have two copies of the mutated allele and so produce the mutated and dysfunctional form for this protein.
-Heterozygote people possess only one normal CFTR allele and a mutated form for the same allele and produce a normal protein and a mutated protein.
In the last case, both alleles are codominant and they express in heterozygote individuals. Given the fact that the normal allele produces enough functional CFTR protein, these individuals do not have any adverse effect and the mutated allele is recessive at a physiological level.
