A cross country runner runs 20 km in 4 hours. what is his average speed

Waves on a pond are an example of which kind of wave? a. sound b. surface c. deep water d. non-mechanical

Which statement best explains why elements are matter? A) The building blocks of elements are small particles called atoms. B) Elements are pure substances that cannot be divided chemically.

What places are likely to support a large producer population? A: Regions where there is no rainfall. B: Areas with abundant water and sunlight. C:Regions with few consumers. D: Ecosystems with many decomposers.

As she starts to move upward, the student pushes down on the surface with a force that is greater than her weight. What can you say about the net force on her? A. The net force is zero. B. The net force is directed upward. C.

The temperature of a system drops by 30°F during a cooling process. Express this drop in temperature in K, R, and °C.

White moths were found in huge numbers in the city of Birmingham. These moths could be easily camouflaged by the trees. Because of sudden industrial development, the trees in the city were covered with soot.

What two factors determine how fast weathering occurs

A sound that's produced by a single wave at a constant frequency and with no overtones is called

Which of the following is ignored when determining the relative mass of atoms? protons nucleus electrons. neutrons

Gamma radiation can be significantly reduced by ... A sheet of paper Air A 3 mm thickness of aluminium Several cm of lead