The Precambrian era envelopes the major bulk of the history of the Earth, beginning from the creation of the planet approx 4.5 billion years ago and terminating with the origination of composite, multicelled forms of life approximately 4 billion years after.
The Precambrian refers to the earliest of the geologic ages that are signified by the distinct layers of sedimentary rock. The Earth was about more than six hundred million years old when life started. The planet had cooled down from its native molten state, creating a solid crust and oceans formed by water vapor in the atmosphere.
At about three billion years ago, the atmosphere of the Earth was virtually devoid of oxygen. At approximately 2.4 billion years ago, oxygen was discharged from the seas as a waste product of photosynthesis by cyanobacteria. The levels of the gas slowly raised, attaining about 1 percent around two billion years ago.
Approximately 800 million years ago, the levels of oxygen attained about 21 percent and started to breathe life into more composite species. The oxygen-rich ozone layer was also created, protecting the surface of the Earth from the harmful solar radiation.
The drugs that are found are <span>Tar, </span><span>Carbon monoxide,</span><span> Nicotine and</span><span>Emphysema </span>
T-A-A-C-G-A
i just finished the quick check this is the right answer
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Answer:
1. The pathway of a red blood cell from the right ventricle to the brain is:
<em>Right ventricle → pulmonary arteries → lungs → pulmonary veins → left atrium → left ventricle → artery aorta → arterial vessels → brain
.</em>
2. The substance that forms hemoglobin in red blood cells when it passes through the lungs is oxyhemoglobin.
Explanation:
Red blood cells are structures present in the blood, whose function is to transport oxygen (O₂) and carbon dioxide (CO₂). This process requires travel throughout the body, through the blood vessels, and gas exchange at the pulmonary and tissue level.
1. A red blood cell in the right ventricle contains carbon dioxide and must pass to the lungs to be oxygenated. The route it takes from there includes Right ventricle (minor circulation) → pulmonary arteries → lungs → pulmonary veins → left atrium → left ventricle → (joining the major circulation) artery aorta → arterial vessels → brain
.
2. The red blood cell or erythrocyte contains a molecule, called hemoglobin, which has an iron core that allows it to bind to O₂ and CO₂ in order to transport them. The affinity for one molecule or another depends on the presence of a certain gas in a certain place.
When the red blood cell passes through the lungs, the concentration of O₂ is higher than CO₂, so the latter is released and O₂ binds to hemoglobin, a conjugation that is called oxyhemoglobin.
Answer: When they were full of air, then the Pressure was the Highest 'cause of the larger force under the specified area as compared to when we released it. We decreased the area of our cheek, so pressure increased and air flows from the cheek (area of high pressure) to the atmosphere
Explanation:
