The correct answer is an accumulation of microorganisms in deep marine environments.
Chalk rock refers to a pure form of limestone produced in tropical and warm seas about 100 million years ago in the Cretaceous period. The microscopic marine algae known as coccoliths thrived in the ancient seas. Their shells were comprised of calcite. With the death of the algae, their bodies sunk to the floor of the sea and sediment of chalk got deposited.
Over many years layers of chalk sediment got deposited and resulted in compaction of loose sediment into solid chalk rock.
Yes, it's important to prevent damage to the nerve cells because if they were to get damaged you could get paralyzed. When your nerve cells are damaged the signals to move different parts of your body don't make it through to the muscles which leads to paralysis.
Answer:
FIRST ONE
Explanation:
Reproduction. Pink salmon in their native range have a strict two year life cycle, thus odd and even-year populations do not interbreed. In the state of Washington, Pink salmon runs occur on odd years. Adult pink salmon enter spawning streams from the ocean, usually returning to the stream where they originated.
Mouth or nose = both openings and cavities
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Pharynx = tubelike passageway on top of the throat
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Larynx = a hollow muscular organ also called the voice box
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Trachea = a large membranous tube
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Bronchi = the major air passages of the lungs
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Lungs = the main organs of the respiratory system
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Bronchioles = any of the minute branches into which a bronchus divides
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Alveoli = microscopic pouches inside lungs where gas exchange occurs
NOTE: Please mark this as brainliest! I truly apologize if there were any mistakes. Hope this helped! :)
