Use the information below to answer questions 1 - 4.

Deformities, such as legs protrucing from stomachs, no legs at all, eyes on backs, and suction cup fingers growing from sides, are turning up with alarming frequency in North American frogs. Extensive studies have been conducted in more than 100 pounds. The data shows that normally about 1% of the frogs are deformed, but in ponds where pesticides are used on surrounding land, as many as 69% of the frogs were deformed. Conclusions from three scientists are given below.

Scientist #1: A molecular biologist from the University of California believes that the deformities may be linked to a new generation of chemicals that mimic growth hormones. He has replicated the same deformities in laboratory experiments using growth hormones.

Scientist #2: A scientist with the Food and Drug Administration believes that the deformities are associated with a by-product of retinoid, which is found in acne medication and skin rejuvenation creams. Her laboratory experiments have shown that retinoids inside a growing animal can cause deformities.

Scientist #3: A developmental biologist from Hartwick College in Oneonta, New York, questions whether a chemical could be the culprit because there were no deformed fish or other deformed animals found in the ponds where deformed frogs were captured. He believes parasites are the cause. When examining a three-legged frog from Vermont, the biologist found tiny parasitic flatworms packed into the joint where a leg was missing.

1. Normally, deformities are found in

O   a. all frog populations
O   b. about 1 % of frogs
O   c. as many as 69% of frogs
O   d. none of these

2. Which scientist believes frog deformities are caused by a new generation of chemicals?

O   a. Scientist #1
O   b. Scientist #2
O   c. Scientist #3
O   d. Scientist #1 and Scientist #3

3. Why does Scientist #3 believe chemicals cannot be the culprit?

O   a. retinoids inside a growing animal can cause deformities
O   b. only about 1% of all frogs have deformities
O   c. growth hormones are not chemicals
O   d. no deformed fish or other deformed animals were found in ponds with deformed frogs

4. What chemical seems to cause deformities in 69% of frogs?

O   a. retinoid
O   b. pesticides
O   c. growth hormones
O   d. parasitic flatworms

Which of the following best accounts for the presence of nitrogen-fixing bacteria in legume root nodules?

O   a. Nitrates are food a source for earthworms.
O   b. Plants can use nitrates, but not nitrogen gas.
O   c. Nitrates are one of the reactants in photosynthesis.
O   d. Nitrogen gas is toxic to most plants, but nitrates are non-toxic.

6. If the environment were to change dramatically or a new plant disease were to break out, which plant represented on the graph would have the greatest chance of survival? O   a. domestic wheat O   b. wild wheat O   c. domestic corn O   d. wild corn

7. The diagram represents succession in a pond. If no human intervention or natural disaster occurs, by the year 2050 this area will most likely be a O   a. lake O   b. swamp O   c. desert O   d. forest

8. What change occurs in the oxygen concentration of the blood as it moves from structure 6 to structure 3? O   a. oxygen concentration does not change O   b. oxygen concentration increases O   c. oxygen concentration decreases O   d. cannot be determined

9. A biologist in a laboratory reports a new discovery based on experimental results. If the experimental results are valid, biologists in other laboratories should be able to

O   a. repeat the experiment with a different variable and obtain the same results
O   b. perform the same experiment and obtain different results
O   c. perform the same experiment and obtain the same results
O   d. perform the same experiment under different experimental conditions and obtain the same results