Which of the following groups of elements are likely to be radioactive? (5 points) a Actinides b Noble gases c Transition metals d BCNOs

What happened in 2012 and how does it illustrate the importance of understanding the sun and how it works?

As air becomes more dense, (select all that apply) o. air weighs less o. gas molecules are closer together o. air is colder o. air weighs more o. gas molecules are further apart o. air is hotter

Who examines and coordinates the cleanup of polluted sites?