What could a skull with large horns or antlers mean?

Why was the sample heated in step 5? describe the chemical principles involved in the reasoning behind this step?

Liquid water turns into water vapor at which step in the water cycle

Look at the following answer choices and determine which belongs in the both category. testable, can be disproven explains natural phenomena, has evidence to support it prediction, tentative, one or more scientists working together well established, many different scientists working independently, highly reliable