Which of the following procedures demonstrates repetition? A. Jeremiah measures the mass of five different strips of metal. He places the strips in five different test tubes filled with hydrochloric acid. He observes if heat and bubbles are produced after the metal strips and acid are combined. B. Cynthia monitors the growth rate of her pet turtle. She measures the length and weight of her turtle every Sunday over the course of six months. C. Marco places a toy car at the top of a ramp. He releases the car and measures how long it takes for the car to reach the bottom of the ramp. Then, he returns the car to the top of the ramp, releases the car again, and makes an additional measurement. D. Kasey performs a scientific investigation on the effects of using soda instead of water to hydrate plants. Caleb uses Kasey's procedure and performs the same experiment during the following month.

The earth's moon is unusually large. two popular theories of the moon's origin include the "sister world" hypothesis, which states that the moon formed from the same materials as the earth, near enough to the earth that they fell into orbit around each other. a second theory is the "capture" hypothesis, in which the moon formed elsewhere in the solar system, and the earth's gravity pulled it into its orbit. studies of what the moon is made of indicate that some of its materials had to come from the earth or from the same area of the solar system where the earth had formed. at the same time, the moon does not contain much of the material that makes up the earth's core, so the moon could not have formed from the same materials as the earth. how do the two facts above affect the described theories of the moon's origin? a. they show that scientists will never agree on where the moon came from. b. they show that more experiments on moon formation need to be done. c. they show that no theory accounts for the existence of the moon. d. they show that neither theory is complete and entirely correct.

Ageochemist examines a piece of metal that he found in the soil. he performs tests to identify the metal from its density, electrical conductivity, and melting point. which statement best describes his investigation? a. he is determining physical properties that are sufficient to identify the metal.b. he is determining chemical properties that are sufficient to identify the metal.c. he is determining physical properties that are insufficient to identify the metal.d. he is determining chemical properties that are insufficient to identify the metal.

Chemistry worksheet - i am not sure what they are asking for exactly?