Undated (AP) _ Here are samples of questions asked at different grade levels in the Second IEA Science Study, and the percentage of U.S. students answering them correctly, where comparable data was available:

Grade 5:

- Flowers cannot usually produce seeds unless

A-they are visited by insects.

B-they appear in the summer

C-they are on plants growing in good soil

D-they produce nectar.

E-suitable pollen is placed on their stigmas.

Correct answer: E, answered correctly by 28.5 percent in 1986, 33.3 percent in 1983, and 32.5 in 1970.

Grade 9:

- When 2 grams of zinc and 1 gram of sulfur are heated together, practically no zinc or sulfur remains after the compound zinc sulfide is formed. What happens if 2 grams of zinc are heated with 2 grams of sulfur?

A-Zinc sulfide containing approximately twice as much sulfur is formed.

B-Approximately 1 gram of sulfur will be left over.

C-Approximately 1 gram of zinc will be left over.

D-Approximately 1 gram of of each will be left over.

E-No reaction will occur.

Correct answer: B, answered correctly by 29.2 percent in 1986, 35.6 percent in 1983, and 33.1 percent in 1970.

First-Year Chemistry:

A mixture of powdered iron and sulfur is heated. What will be formed?

A-a single element

B-two other elements

C-a solution

D-an alloy

E-a compound

Correct answer: E, answered correctly by 70.2 percent in 1986, no comparable data for previous years.

Second-Year Physics:

A stone is thrown upward at an angle of 45 degrees. At the highest point reached by the stone, which one of the following is true?

A-Acceleration is zero.

B-Acceleration is at a minimum, but not zero.

C-Total energy is at a maximum.

D-Potential energy is at a minimum.

E-Kinetic energy is at a minimum.

Correct answer: E, answered correctly by 54.3 percent in 1986, no comparable data for previous years.