The Great Oxidation Event (GOE), sometimes also called the Great Oxygenation Event, Oxygen Catastrophe, Oxygen Crisis, Oxygen Holocaust,[2] or Oxygen Revolution, was a time period when the Earth's atmosphere and the shallow ocean first experienced a rise in oxygen, approximately 2.4 billion years ago (2.4 Ga) to 2.1–2.0 Ga during the Paleoproterozoic era.[3] Geological, isotopic, and chemical evidence suggests that biologically produced molecular oxygen (dioxygen, O2) started to accumulate in Earth's atmosphere and changed Earth's atmosphere from a weakly reducing atmosphere to an oxidizing atmosphere,[4] causing many existing species on Earth to die out.[5] The cyanobacteria producing the oxygen caused the event which enabled the subsequent development of multicellular forms.
The answer is (2). If you recall Rutherford's gold foil experiment, remember that a stream of positively charged alpha particles were shot at a gold foil in the center of a detector ring. The important observation was that although most of the particles passed straight through the foil without being deflected, a tiny fraction of the alpha particles were deflected off the axis of the shot, and some were even deflected almost back to the point from which they were shot. The fact that some of the alpha particles were deflected indicated a positive charge (because same charges repel), and the fact that only a small fraction of the particles were deflected indicated that the positive charge was concentrated in a small area, probably residing at the center of the atom.
Answer:
A. Fossils of organisms that lived in warm climates have been found in arctic environments.
Explanation:
One of the logic used by Geologists to justify plate movement over a region of space is that the fossils of organisms that lived in warm climates have been found in arctic environments.
- this is as a result of plate tectonics.
- organisms that are well adapted to warm climates in times past have their relics preserved as fossils.
- their fossils are no found today around the arctic environment which are cold
- this suggests that the plate must have drifted or moved
The hydrogen bonding in H₂O is stronger than that of HF
Explanation:
Hydrogen bonds are special dipole-dipole attraction in which electrostatic attraction is established between hydrogen atom of one molecule and the electronegative atom of a neighboring molecule.
- The strength of hydrogen bonds depends on the how electronegative an atom is.
- Electronegativity refers to the tendency of an atom to gain electrons.
- The higher the value, the higher the tendency.
- This why oxygen with a higher electronegativity will form a stronger hydrogen bond with hydrogen compared to fluorine.
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Answer:
gravaity is the force that helps you