Is this a metal or non metal; a shiny substance used to make flexible bed springs

What happened to the amount of carbon dioxide in the atmosphere from 2010–2017?

Skills of homo sapiens were found an excavation. the skulls were preserved because the bodies were frozen. so, these fossils are (blank) fossils.the image shows the evolution of skulls beginning 2 to 3 million years ago. based on the image, modern human skulls(blank) ape skulls.

Avariable that is not being directly tested during an experiment should be changed varied experimented controlled