What Helps Maintain Global Oxygen Concentrations in the Troposphere

question 2

Multiple Choice

What helps maintain global oxygen concentrations in the troposphere?

• A)Oxygen levels remain balanced by photosynthesis and cellular respiration.
• B)Photosynthesis replaces oxygen loss to air pollutants like NOx, SOx, and ozone.
• C)The burning of fossil fuels since the Industrial Revolution has helped maintain oxygen concentrations in the atmosphere.
• D)Excess oxygen is broken down by ozone in the upper atmosphere.

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Definitions:

Net Present Value

A calculation that compares the value of a dollar today to the value of that same dollar in the future, taking inflation and returns into account.

Required Rate

The minimum return an investor expects to achieve when investing in a particular asset or project.

Payback Period

The duration of time it takes for an investment to generate enough revenue to recover the initial cost of the investment.

Profitability Index

A measure used in capital budgeting to evaluate the profitability of an investment, calculated as the present value of future cash flows divided by the initial investment cost.