The correct answer of the given question above would be option D. The option that did not occur during the Cenozoic era is the formation of the ozone layer. The ozone layer has long been there before any era since it is part of the earth's atmosphere. Hope this answer helps.
SA Node<span> which is also known as the sinus node, is the natural pacemaker of
the heart. It controls the heart rate by generating electrical impulses
and then sending electrical signals through the heart muscle, causing
the heart to contract and pump blood throughout the body. </span>
The SA Node is located in the outer layer of the right atrium of the heart, near the superior vena cava. It is made up of a group of cells (myocytes) positioned on the
wall of the right atrium, at the center of the heart and near the
entrance of the superior vena cava. These cells contract at a rate of
about 70-80 times per minute, which make up the natural heart beat.
In the heart, the valves are located between atria and ventricles and between ventricles and arteries (option D).
<h3>What are valves in the heart?</h3>
Valves are membranous partitions which permit the passage of the contents of a vessel or cavity in one direction, but stop or control the flow in the opposite direction.
Valves in the heart enforce a one-way blood flow through the heart and separate atria from ventricles, and ventricles from the large arteries that leave them.
The four valves in the heart and their location is as follows:
- tricuspid valve: located between the right atrium and the right ventricle
- pulmonary valve: located between the right ventricle and the pulmonary artery
- mitral valve: located between the left atrium and the left ventricle
- aortic valve: located between the left ventricle and the aorta.
The valves between the atria and ventricles are called atrioventricular valves or cuspid valves while those at the bases of the large vessels leaving the ventricles are called semilunar valves.
Therefore, it can be said that the valves of the heart are located between atria and ventricles and between ventricles and arteries.
Learn more about valves of the heart at: brainly.com/question/28266922
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Although the options are not provided, the statement best describing the relationship is nucleic acids provide blueprints for the construction of proteins.
Messenger RNA molecules (mRNA) take instructions from DNA molecules and take the code out of the nucleus. There, ribosomes work with the RNA molecules to produce a chain of amino acids, which in turn links and folds in a specific manner to form a protein molecule.
