Identify whether the description refers to a monomer, a polymer, or both. macromolecule: repeating units: simple molecule: covalent bonds:

Nucleic acid certain protein cell membranes certain carbohydrates

1) what three conditions must be present for minerals to form through natural processes? 2) why are minerals considered inorganic substances? 3) how do oxides differ from other minerals that contain oxygen atoms? 4) how is a sulfide different from a sulfate? what makes native elements unique?

The cretaceous period spanned the time interval between and 65 million years ago. 250 million 144 million 75 million 200 million