Answer : True
Enrichment cultures are used to increase a small number of desired organisms
Answer:
Cells are the basic building blocks of living things. The human body is composed of trillions of cells, all with their own specialised function.
Answer:
B) The "lub-dub" sound originates from blood turbulence through the heart.
Explanation:
The systole and diastole in the heart produce the lub and dub sound in the heart.
The systole represents the contraction of both left and right ventricles and pumps the blood to the body and the right ventricle to the lungs. This involves the opening and closing of the valves. The closing of the atrioventricular valves produces lub sound.
At the end of the systole or ventricular contraction or when the blood has been pumped to the aorta and the pulmonary valves then the semilunar valves present in the aorta and pulmonary closes. This produces a sound dub.
Therefore,lub dub is associated with the physical contraction of the heart but not the turbulence of the blood.
Thus, the selected option is the correct answer.
Answer:
No, The respiratory system does not work alone in transporting oxygen through the body. The respiratory system works directly with the circulatory system to provide oxygen to the body. Oxygen taken in from the respiratory system moves into blood vessels that then circulate oxygen-rich blood to tissues and cells.
Explanation:
Hope that helps!
B) Around 300 million years ago, the regions where coal formed were located in tropical climates that were partially submerged on the coasts
Explanation:
The distribution of the world's major coal reserves supports the the theory of plate tectonics because the regions where they formed were in tropical climates around 300 million years ago.
Coal is a fossil fuel used to produce energy when burnt.
They are formed in tropical swamps where there is luxuriant plants life.
To form a coal, a terrain such as swamp must have rich plant life. The plant is rapidly buried and cut off from the oxic environment. Further burial under heat and pressure transforms the plant matter into coal.
- The major reserves of coal in the world today is found in Europe and North America
- These are temperate regions whose conditions do not favor the formation of coal.
- Those regions must have moved from around the equator to their present day position.
- The coal formed when they were much closer to the equator around 300 million years ago.
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Sea floor spreading brainly.com/question/9912731
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