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Use the following information to answer questions 12 and 13. 14. The algae population of a lake in the Midwest United

States has increased dramatically within the past few
The bright coloration of beaks is an important indicator
12. Which could be a null hypothesis for this experiment? FINAL. For review purposes only - do not post.
of body condition and overall health in birds. The inten- years. A group of researchers has hypothesized that
sity of the color is heavily based on a type of pigment this is due to an abundance of phosphorus in the water
called carotenoids. Carotenoids can be found in many of caused by fertilizers used on nearby lawns. Which is
the foods that birds consume. Researchers manipulated the best way to test this hypothesis?

the diets of male zebra finches with a combination of (A) Set up multiple tanks of water and add different
good- or poor-quality food and the presence or absence concentrations of the fertilizer rich in phosphorus
of carotenoids. The color of the beak was then measured, to the tanks. Observe and measure the algal growth.

with high chroma signifying a bright color. The results (B) Continue observing the algae growth in the lake.
are shown in the figure below. Compare its growth to areas around the lake that do
not have lawns.

1.0 (C) Take water samples from the lake to quantify the
Red chroma intensity (saturation) 0.6 A B C D (D) Remove the algae from the lake and use it to start an
exact amount of phosphorus in each area. Use these
0.8
data to add phosphorus back into the lake and

observe the growth.

algal culture in a lab setting. Place different amounts
0.4

of algae in clean water and see if it survives.

0.2

cellular environment of pH 7.4. As the pH becomes
0 15. The amino acid glutamine is ionized in a neutral
Food+/Car+ Food+/Car– Food–/Car+ Food–/Car– more acidic, glutamine becomes a positive ion. What is
+
−

Food and carotenoid (Car) treatment the relationship between H and OH ions in solution

Effect of food and carotenoid intake on beak coloration. Data from https:// in an environment with a pH of 5.4?
+
www.nature.com/articles/srep23546 (A) There would be 2 times fewer H ions and 2 times

−
more OH ions in solution.

©2022 BFW Publishers. PAGES NOT

+
(B) There would be 10 times fewer H ions and

(A) Good-quality food and the presence of carotenoids 10 times more OH ions in solution.
−

will result in a bright red beak.
+
(C) There would be 20 times more H ions and

(B) Only birds with diets rich in carotenoids will have 20 times fewer OH ions in solution.
−

bright beaks. Food quality does not matter.
+

(D) There would be 100 times more H ions and
(C) Beak color intensity will not be influenced by food 100 times fewer OH ions in solution.

−

quality or the presence of carotenoids.
(D) A diet of poor quality and low in carotenoids yields

dull coloration.
13. Based on the error bars in the graph, which two treat-
ments are significantly different from each other?
(A) A and C (C) B and C
(B) A and D (D) B and D
®
90 UNIT 1 cHeMisTRY OF liFe UNIT 1 AP PRAcTice QuesTiONs 91
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