Please Use the Following Information to Answer the Questions Below

question 7

Multiple Choice

Please use the following information to answer the questions below.
A scientist conducts an experiment to quantify the effect of mycorrhizae and soil nitrogen levels on plant growth in a grassland.The experiment has four treatments: (1) mycorrhizae present and ambient levels of nitrogen, (2) mycorrhizae present and nitrogen added, (3) mycorrhizae absent and ambient levels of nitrogen,and (3) mycorrhizae absent and nitrogen added.After four weeks,the scientist removes the aboveground plant material for weighing.
Figure 42.4
-Figure 42.4 shows the results of the experiment.What is (are) the independent variable(s) ?

• A)nitrogen treatment only
• B)biomass of aboveground plant only
• C)presence and absence of mycorrhizae
• D)nitrogen treatment and whether mycorrhizae are present

---

Definitions:

Future Value

The estimated amount of money an investment is projected to grow to, based on a specified rate of interest or return over a set period.

Present Value

The current estimation of a future quantity of money or sequences of cash inflows, figured with an explicit rate of return.

Serial Bonds

Bonds that mature in installments at regular intervals over a period of time rather than having a single maturity date.

Debenture Bonds

Unsecured bonds that rely on the creditworthiness and reputation of the issuer for support, rather than collateral.