Define atomic number and atomic mass number under what conditions are two atoms different isotopes of the same element?

Atrain travels 74 kilometers in 3 hours, and then 81 kilometers in 5 hours. what is its average speed?

Predict the products butane (c4h10) + oxygen —>

Transportation is the largest single source of air pollution in the united states. air pollution can harm the environment and human health. which technology could offer a solution to this problem? mufflers that reduce noise motors that run on electricity tires that improve gas mileage