How do you know this? The experiment had multiple variables. The experiment had one variable. The experiment had no changing variables.

The table shows dates and appearance of index fossils. which rock layers can be dated most precisely? a) a layer containing both a fossil 4 and a fossil 3 b) a layer containing both a fossil 2 and a fossil 3 c) a layer containing both a fossil 1 and a fossil 4 d) a layer containing both a fossil 1 and a fossil 2

Isotopes of the same element have differ in their

Which of the following describes research that would be considered basic science? a. a farmer is trying to improve his crop yields by using a new kind of fertilizer. b. a college students is curious about the growth of desert pants in the presence of excess amounts of water. c. government officials are trying to prevent the spread of new strain of influenza virus. d. a doctor is trying to determine why a patient is feeling tried and sick. b.a college students is curious about the growth of desert pants in the presence of excess amount of water