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Citrus2011 [14]
3 years ago
13

Identify the structure of the human heart which is a valve that closes during each heartbeat to prevent blood from flowing back

into the right ventricle from the pulmonary trunk.
Biology
1 answer:
Scilla [17]3 years ago
5 0

The answer is pulmonary

valve. The pulmonary valve is found between the right ventricle and the pulmonary artery. The valve is a semi-lunar valve that opens when the pressure in the right ventricle is higher than that in the pulmonary artery (because the ventricle is filled with blood). When the ventricle pumps blood into the pulmonary artery, the pressure in the artery rises while that in the ventricle lowers. This closes the pulmonary valve preventing the backflow of blood into the right ventricle. Pulmonary artery takes blood to the lungs for oxygenation.

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This theory is excepted by scientist when
Arada [10]

Answer:

Explanation:

If enough evidence accumulates to support a hypothesis, it moves to the next step — known as a theory — in the scientific method and becomes accepted as a valid explanation of a phenomenon. Tanner further explained that a scientific theory is the framework for observations and facts.

3 0
3 years ago
1.Which of the following correctly describes a reaction that forms a disaccharide from two monosaccharides?
coldgirl [10]

The correct answer is:

<h2>Glucose + fructose → sucrose </h2><h3>Explanation;</h3>

Glucose and fructose are monosaccharides and are the building blocks of sucrose, a disaccharide. Thus, disaccharides are just a pair of associated sugar molecules. disaccharide.  They are remunerated when two monosaccharides are joined together and a molecule of water is eliminated -- a dehydration reaction.

2.The correct answer is:

<h3>d.The nucleic acid is DNA and would be found in the cell's nucleus.</h3><h3>Explanation:</h3>

The scientist can say with confidence that this DNA molecule is enclosed by a nucleus based on the combination of the nucleic acid defined. Only eukaryotic cells have a ladder structure. The prokaryotic cells have circular DNA and do not have any organelles, like the nucleus. Consequently, from the steps structure of the DNA, the scientist can see that the cell has a nucleus.

3.The correct answer is:

a.Enzyme activity will decrease, and the reaction will proceed very slowly, or possibly not at all.

Explanation:

The enzyme work under a standard conditions.they work under an optimized conditions if any of them is increased or decreased enzyme activity will b effected.

4.The correct answer is:

a.Adding an enzyme to decrease the activation energy of the reaction

<h3>Explanation:</h3>

Enzymes are macromolecular biological catalysts. Enzymes excite chemical reactions. The particles upon which enzymes may act are called substrates and the enzyme transforms the substrates into separate molecules known as outcomes.

5.The correct answer is:

a.As technology improves so will our understanding of cells.

Explanation:

The advancement in technology improves the understanding of cell and enables the scientist to learn about cell in more detail.

6.The correct answer is:

c.builds on the work of earlier scientists

<h3>Explanation:</h3>

As new work comes to light, a theory is changed; however, it cannot be terminated because one concrete research providing testimony toward it can disprove it.

7.The correct answer is:

b.The lipids and proteins that make up the membrane allow it to be selective about what enters and leaves the cell.

Explanation:

It consists of a lipid bilayer with embedded proteins. The basic function of the cell membrane is to protect the cell from its surroundings. The cell membrane controls the movement of substances in and out of cells and organelles. In this way, it is selectively permeable to ions and organic molecules.

8.The correct option is:

d.fewer mitochondria since there will be fewer molecules left in the cell.

Explanation:

To actively transport molecules against its concentration gradient wanted energy which is generated by the ATP hydrolysis. As mitochondria make and store ATP, here more mitochondria are required to meet the increased energy requirement.

9.The correct answer is:

A protein acts as a pump and moves calcium ions from an area of low concentration to an area of high concentration.

Explanation:

Active transport is the transportation of molecules beyond a membrane from a region of their lower concentration to a region of their greater concentration—in the regulation against the density gradient.

10.The correct answer is:

d.Mitochondrium

Explanation:

The mitochondrion is a double-membrane-bound organelle found in most eukaryotic bodies. Some cells in some multicellular organisms may, though, lack them and present in plants and animal cell.

6 0
3 years ago
Read 2 more answers
Estimate the maximum time a person could listen to a sound of 87 decibels.
Kazeer [188]

The maximum time a person could listen to a sound of 87 decibels is: 8 hours

<h3>Meaning of Decibels</h3>

Decibels can be defined as the unit used by scientists to measure sound level.The values of Decibel ranges from a very low value to a very high value and the higher we get the more dangerous it is to our human ear.

In conclusion, The maximum time a person could listen to a sound of 87 decibels is 8 hours

Learn more about Decibels and human hearing : brainly.com/question/1291668

#SPJ1

4 0
2 years ago
Someone help me please I’ll make brainlist!! Quick fast
yulyashka [42]

Answer:

I think this is 2 because there would have been bigger predators in the ocean vs. a lake

4 0
3 years ago
what term describe Movement of gases across the respiratory membrane in the pulmonary capillaries or into the alveoli?
Pavlova-9 [17]

Answer:

<em>At the respiratory membrane, where the alveolar and capillary walls meet, gases move across the membranes, with oxygen entering the bloodstream and carbon dioxide exiting. It is through this mechanism that blood is oxygenated and carbon dioxide, the waste product of cellular respiration, is removed from the body.</em>

<em></em>

8 0
3 years ago
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