Answer:
The semilunar valves prevent backflow of blood into the ventricles.
Explanation:
The semilunar valves are valves found at the junction between the left ventricle and the aorta and also between the right ventricle and the pulmonary artery. They are cup-like in shape and prevent blood from flowing back into the ventricles which are the pumping chambers.
There are two types of semilunar valves. The aortic semilunar valves and the pulmonary semilunar valves. They are made up of the endocardial and connective tissue.
The closure of the semilunar valves causes the second heart sound detected on the stethoscope.
Diseases that arise from the semilunar valves are caused by its stenosis which is the narrowing of the valves and regurgitation where the heart valves can no longer hold firm enough to prevent the backflow of blood.
The genotype of a heterozygous individual is Aa, of a homozygous dominant is AA, and of a homozygous recessive individual is aa.
<h3>What is a dominant genotype?</h3>
A dominant genotype is a set of gene variants characterized to have dominant alleles that mask the expression of recessive alleles in heterozygous individuals in cases of complete dominance.
In conclusion, the genotype of a heterozygous individual is Aa, of a homozygous dominant is AA, and of a homozygous recessive individual is aa.
Learn more about dominant genotypes here:
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Answer:
dear user the answer is option A.oxygen level and water temperature and C.salinity and water temperature.
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Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution.
