According to Geological Evidence and Computer Models Based on That

question 7

Multiple Choice

According to geological evidence and computer models based on that evidence,which statement about the concentration of oxygen in our atmosphere is correct?

• A)No oxygen was present prior to the Cambrian Era;oxygen levels have uniformly risen since,and today's atmosphere is more oxygen rich than at any time in Earth's history.
• B)Oxygen levels were greatest during the Cambrian Era but have been steadily declining ever since;today's atmosphere is less oxygen rich than at any time in Earth's history.
• C)Oxygen levels have generally risen during the Phanerozoic Era but peaked during the Mesozoic Era (Age of Dinosaurs)and declined sharply in the Early Cenozoic Era.
• D)Oxygen levels have generally risen during the Phanerozoic Era but peaked during the Late Paleozoic Era (the time of coal swamp forests)and declined sharply in the Early Mesozoic Era.

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Definitions:

Profit Margin Ratio

A financial metric that measures the percentage of revenue that exceeds the cost of goods sold, indicating the profitability of sales.

Net Income

The total earnings of a company after deducting all expenses, taxes, and losses, indicating the company's profitability.

Net Sales

The revenue from sales after deducting returns, allowances for damaged or missing goods, and discounts.

Times Interest Earned

A metric that measures a company's ability to meet its interest payments on outstanding debt.