It is not possible for Sarah and Thomas to develop cystic fibrosis but it would be possible for one of their children to inherit it. Both Sarah and Thomas are heterozygous and in a heterozygous pair of alleles the dominant allele is the one that will present. Because Sarah and Thomas both have the heterozygous allele combination Ff they are carriers which means that they will not experience symptoms of cystic fibrosis but they could pass cystic fibrosis onto one of their children.
The blood vessels farthest from the heart must have valves.
The valves which are present in the blood vessels prevent the backflow of the blood back into the specific organ.
There are different valves present in the heart are:
- The tricuspid valve is situated between the right atrium and right ventricle.
- The pulmonary valve is between the right ventricle and the pulmonary artery.
- The mitral valve is between the left atrium and left ventricle.
- The aortic valve is between the left ventricle and the aorta.
Other vales which are present in the blood vessels are in leg. Leg veins do require the valves. If not present the blood will go back down into the feet because of the gravity. Thus there are various valves present in the leg veins.
Valves in veins are bicuspid, meaning they have two flap-like structures that regulate blood flow in the vein.
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The answer is <span>A. codon ® gene ® DNA ® chromosome.
</span>Codons are base triplets (three nucleotide bases) on DNA.
Genes are sequences of DNA that typically contain the code for
a particular protein.
<span>DNA is a two-stranded helix consisting of nucleotides.
</span>Chromosomes consist of DNA molecule that is packaged into thread-like structure.
