I need help with this Webassign for Physics class. The questions are on the screenshot.

Do you agree with scientist’s prediction about the warming of alaska and other polar regions?

Engineers find a new metal that is stronger than steel but much lighter. this material is also significantly cheaper than what is currently used for most aircraft, available in large quantities, and easy to manufacture. the engineers are excited because this new material will lower the costs of buying and operating airplanes for companies. what is probably the best step for the engineers to make next?

The least penetrating form of radiation is